> For the complete documentation index, see [llms.txt](https://en.help.firstline.cc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://en.help.firstline.cc/feature/channels/phone/yi-nan-za-zheng.md).
# Troubleshooting
Quickly troubleshoot FIRST LINE phone issues by scope of impact and common symptoms, from self-checks for a single agent to large-scale enterprise incidents.
## Overview
FIRST LINE's internet telephony uses **WebRTC (Web Real-Time Communication)** and **WebSocket** and other technologies to maintain real-time voice, call status, and system connections in the browser. In short, these technologies let you answer and make calls directly in FIRST LINE without installing traditional phone software.
Unlike ordinary web browsing or watching videos, telephony is real-time communication and is more sensitive to network stability. Even if the network speed looks normal, brief outages, latency, or packet loss can still cause choppy audio, one-way silence, abnormal call status, or even dropped calls.
Therefore, when you encounter phone issues, it does not necessarily mean FIRST LINE itself is malfunctioning; it may also be related to browser permissions, your device, the network environment, enterprise telecom lines, or the Gateway. This page will first help you determine the issue's**handling level**and then troubleshoot step by step according to the symptoms.
## First, determine the handling level
When a phone issue occurs, the first step is not to immediately adjust your computer or network settings, but to first confirm the**scope of impact**.
```mermaid
flowchart TD
A[Phone function abnormal] --> B{Scope of impact?}
B -->|Only one or a few agents| C[Individual environment troubleshooting]
B -->|Many or all agents| D[Enterprise-wide issue handling]
C --> E[First complete the quick 4-step check]
E --> F{Back to normal?}
F -->|Yes| G[Complete]
F -->|No| H[Further troubleshoot by symptom]
D --> I[Check line / Gateway / system status]
I --> J[Contact FIRST LINE if necessary]
classDef normal fill:#E8F1FF,stroke:#4A78C2,color:#1F2937;
classDef caution fill:#FFF4CC,stroke:#C99700,color:#1F2937;
classDef danger fill:#FFE3E3,stroke:#C94A4A,color:#1F2937;
classDef success fill:#E5F6E8,stroke:#4E9B5F,color:#1F2937;
class A,B,C,E normal;
class H caution;
class D,I,J danger;
class G success;
```
{% hint style="warning" %}
**If at the same time many or all agents cannot log in, cannot receive calls, or cannot make calls, there is usually no need to check each computer one by one.**
Please go directly to the handling method for "enterprise-wide issues" on this page.
{% endhint %}
***
## Single agent: first complete the quick 4-step check
Most phone issues encountered by a single agent can be handled by completing the following four steps in order.
{% stepper %}
{% step %}
### Refresh FIRST LINE
Refresh the page so the phone function reconnects, then check whether it has returned to normal.
{% endstep %}
{% step %}
### Check phone status and browser permissions
Confirm that you are currently logged in to the phone, and check whether the browser allows FIRST LINE to use the microphone and desktop notifications.
{% endstep %}
{% step %}
### Check whether the network is normal
Open other web pages to confirm the network is still working normally. If the environment allows, it is recommended to use a wired network rather than Wi-Fi.
{% endstep %}
{% step %}
### Test in Incognito mode or another browser
If everything above is normal, you can log in again and test using Chrome Incognito mode, Edge InPrivate mode, or another supported browser.
{% endstep %}
{% endstepper %}
If the problem still has not been resolved, check the handling methods below according to the symptom you are experiencing.
***
## Cannot log in to the phone
### Check microphone and browser permissions
Before logging in to the phone, first confirm that the microphone device is correctly connected and enabled.
If prompts such as "Cannot access your microphone or headset" appear during login, please allow the browser to use:
* Microphone
* Desktop notifications
If permissions are not enabled, you may not be able to log in to the phone properly or make calls.
You can click the site information / lock icon in front of the browser address bar, set the relevant permissions to "Allow", and then refresh the page.
### Check whether phone licenses are fully used
Phone seat licenses and FIRST LINE's general system licenses are counted separately.
If the number of devices currently logged in to the phone has reached the purchased license limit, new devices will not be able to log in. For example, if the company purchased 5 phone extension licenses and 5 are currently in use, the 6th may not be able to log in.
You can check the number of phone extensions currently purchased by the company from the "Subscription Plan" in the system.
{% hint style="info" %}
In general, the number of phone extensions available in the system will match the purchased licenses; however, if the company has configured more extensions due to shift work or during rollout, the number of extensions may exceed the actual licensed count.
{% endhint %}
***
## Cannot make outbound calls
First confirm:
1. The phone is currently logged in and the status is normal.
2. The phone number format and content being dialed are correct.
3. Refresh the page and try again.
4. If only you cannot make outbound calls, then check the network and browser environment again.
### Common outbound call error messages
| Error message | Common cause | Recommended handling |
| -------------------------------------------------- | ------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------- |
| **The dialed number does not exist or is invalid** | Incorrect number entered, number does not exist, or international number format is incomplete | Confirm the full phone number; for international calls, include the correct country code and area code. |
| **The dialed number is temporarily unreachable** | The other party rejected the call, powered off the phone, is in airplane mode, or has poor signal | Try again later, or contact them using another method. |
| **The other party is busy** | The other party is on a call | Try calling again later. |
| **Call canceled** | The call was canceled or ended early | Confirm whether the call was accidentally hung up, then dial again. |
| **The dialed number is currently unavailable** | Number deactivated, service suspended, or temporarily unreachable | Try again later, or use another contact method. |
***
## No incoming call notification or ringing
If other agents can receive calls normally but only you do not ring, please confirm in order:
1. Whether the phone is logged in.
2. Whether the phone status is the "Ready" state that can accept assignments.
3. Whether the page has shown a disconnection or reconnection prompt.
4. Refresh FIRST LINE so the phone reconnects.
5. Confirm browser permissions and network status.
6. Use Incognito mode or another browser for cross-testing.
If many or all agents do not receive calls at the same time, please go directly to "enterprise-wide issues".
***
## No sound in the call, volume too low, or noise
### First check the audio devices
Confirm:
* The microphone and headset / speakers are correctly connected.
* The browser allows FIRST LINE to use the microphone.
* The operating system has not muted the browser.
* The headset or microphone is not being used by another application or the wrong device is not selected.
### Check the operating system volume
If you are using Windows, you can open the "Volume Mixer" from the volume icon in the taskbar to confirm that the browser application's and the main output device's volume settings are normal.
### Check network quality
Internet telephony requires a continuous and stable connection. Even if normal web pages still open properly, brief interruptions, latency, or packet loss can still cause:
* Choppy audio
* Latency
* Noise
* One-way silence
* Call drop
If the environment allows, it is recommended to use wired Ethernet to reduce the impact of Wi-Fi interference or instability.
{% hint style="info" %}
**Network speed is not the same as network quality.**
Real-time calls require not only sufficient bandwidth, but are also affected by connection stability, latency, and packet loss. Therefore, "normal speed test results" do not necessarily mean call quality is completely normal.
{% endhint %}
### If the microphone volume keeps getting lower by itself
The following are more advanced browser settings, and it is recommended to use them only when "microphone input volume is automatically adjusted".
Using Chrome as an example:
1. Enter in the address bar `chrome://flags/`.
2. Search for `webrtc`.
3. Find `Allow WebRTC to adjust the input volume`.
4. Change the setting to `Disabled`and then restart the browser.
{% hint style="warning" %}
`chrome://flags/` This is a Chrome experimental setting. If you are not experiencing automatic microphone volume changes, do not adjust other items yourself.
{% endhint %}
***
## Phone status automatically changes to not ready or logged out
When you log out of FIRST LINE for a period of time, the phone status will automatically change to "not ready" so that new calls are not still assigned to agents who can no longer answer.
If you did not actively log out but the phone suddenly becomes not ready or disconnected, common reasons include:
* The network was briefly interrupted.
* The computer entered sleep or power-saving mode.
* The browser put tabs that were unused for a long time to sleep or reduced their execution frequency.
* Browser extensions, cache, or other settings affected the connection.
The system may also display reconnection-related prompts in some disconnection scenarios.
### Reduce the chance of automatic disconnection
* Prefer a stable wired network.
* Avoid letting the work computer enter sleep mode during service hours.
* If the company has screen lock or power-saving policies, confirm with internal IT whether they will interrupt the network or the browser's background connection.
* You can use Incognito mode for testing to confirm whether it is caused by extensions or the browser environment.
* If Edge or Chrome has sleep tabs / memory saver features enabled, ask IT or an administrator to help confirm whether FIRST LINE is affected.
Edge
***
## Use Incognito mode or another browser for cross-testing
If the network, microphone, and phone status are all normal but the problem persists, you can test in a clean browser environment.
Recommended:
1. Open Chrome Incognito mode or Edge InPrivate mode.
2. Log in to FIRST LINE again.
3. Allow the necessary microphone and notification permissions.
4. Test the phone function again.
If Incognito mode works normally, the original browser environment may be affected by extensions, cache, or other settings.
{% hint style="info" %}
Some extensions can be configured to still run in Incognito mode, so Incognito mode does not necessarily equal a completely new browser environment. If the problem persists, further disable extensions or try another browser for cross-testing.
{% endhint %}
***
## Enterprise-wide issues
If any of the following occurs at the same time, it is recommended not to check each agent's computer one by one:
* Many or all agents cannot log in to the phone.
* Many or all agents cannot make outbound calls.
* Customers generally cannot call into the enterprise service phone.
* Multiple agents experience dropped calls or obvious quality issues at the same time.
FIRST LINE's phone service is integrated with the enterprise's own telecom lines, phone equipment, and system connections. Some enterprises may use dedicated lines provided by telecom service providers, as well as physical Gateway devices to handle inbound and outbound calls.
Therefore, large-scale issues may require checking the following at the same time:
* Enterprise telecom line status
* Gateway or related phone equipment
* Enterprise network environment
* Connection status between FIRST LINE and the phone system
{% hint style="danger" %}
If you confirm that many or all agents are affected at the same time, please contact FIRST LINE customer service for assistance. There is no need to ask each agent to repeatedly clear cache or adjust their personal device settings.
{% endhint %}
### Prepare before contacting FIRST LINE
To help locate the issue faster, it is recommended to provide:
1. **Time the issue occurred**: including the date and approximate time.
2. **Relevant phone information**: for example, phone number, service record number, or other identifiable data.
3. **scope of impact**: single agent, some agents, or all agents.
4. **System environment**: if the company has multiple FIRST LINE environments, please provide the environment name or login URL.
5. **Actual symptom**: for example, "completely silent after outbound dialing" or "all agents cannot log in to the phone", rather than just "there is a phone problem".
{% hint style="warning" %}
Please avoid providing only recordings or information like "there is a problem" or "the sound is unclear". The time the issue occurred, scope of impact, and identifiable call records are usually more helpful for locating the cause.
{% endhint %}
***
## Advanced: Why does the network affect calls?
Understand the difference between real-time calls and ordinary web use
FIRST LINE's internet telephony uses WebRTC, WebSocket, and other real-time communication technologies to maintain audio and call status connections.
Ordinary video streaming can temporarily compensate through buffering when the network is briefly unstable; real-time calls cannot wait long for data to be retransmitted, so brief network interruptions, latency, or packet loss are more directly reflected in audio and call connectivity.
This is why calls may still experience dropped audio, latency, or brief disconnections even when ordinary web browsing or watching videos seems normal.
Advanced checks for the enterprise network environment
If the problem only occurs on the enterprise office network, ask internal IT to help confirm:
* Whether VPN is being used, and whether the VPN affects real-time communication.
* Whether the firewall or security software restricts the necessary call connections.
* Whether the wireless network has signal interference or instability.
* Whether computer sleep, power saving, or enterprise security policies interrupt background network connections.
Ordinary users are not advised to broadly loosen firewall or security settings themselves; if you suspect the issue is related to enterprise network policies, please have IT personnel help confirm it.
