Troubleshooting
😞 Unable to send message
1. The customer sent a message more than 24 hours ago or received a notice such as This message is sent outside of allowed window
Due to Facebook Messenger's privacy rules, ifthere is no reply within 24 hours, the Page cannot send messages to that user.
This policy exists to protect customers from unsolicited messages and spam. If the customer contacts you, your support team will be able to send messages within the next 24 hours. If you send a message after 25 hours, your message will be rejected by Facebook.If the user sends a new message, you will be able to contact this customer again.
2. The authorized Facebook user's password was changed
If you changed the password, FIRST LINE needs to be reconnected to Facebook following the steps above.
3. The authorized Facebook user account enabled two-factor authentication
If you enabled two-factor authentication after authorization, FIRST LINE needs to be reconnected to Facebook following the steps above.
4. An error message occurred
#190
Error validating access token or Error validating access token: The session has been invalidated because the user changed their password or Facebook has changed the session for security reasons
When you see such an error message, it means your authorization has expired, preventing data access. This often happens because the authorized person changed the Instagram or Facebook password associated with the system, or the session was invalidated for security reasons. If Facebook detects suspicious activity, they may take the measures described above.
Please have the original authorizer or another Page admin with the same permissions reauthorize in the system according to the documentation.
#551
This user is currently unavailable, this user cannot receive your messages at the moment
This could indicate the user has blocked your Page or that the user has deactivated their account.
#100
Upload attachment failure.
Meta does not accept this file, possibly due to the following reasons:
1. File corruption: please check whether the file is intact and undamaged.
2. Unsupported file extension: ensure you use mainstream formats like jpeg, jpg, png, etc.
3. File extension does not match the actual file type: for example, a jpg file renamed as png; use the correct file format.
In rare cases this can be due to an official Meta issue (this has happened). Please try again later.
Please try using the following mainstream formats: JPEG / JPG / PNG, etc. Ensure your file format is correct and try uploading again
#10
This message was sent outside of the allowed window This message is sent outside of allowed window
Indicates the reply time allowed by Facebook has been exceeded, i.e. the "24+1" policy. This means that after Facebook sends a message to a user, if the user does not reply within 24 hours, you can only proactively send one more message. If the user still does not reply to that message, you cannot push more messages to that user. This is a Facebook usage restriction to ensure compliance and provide a good user experience.
#-1
Unexpected internal error
Means Facebook encountered an unexpected error; try your request again later.
#-2
Timed out while uploading message attachment; please try again later
Means Facebook encountered an unexpected error; try your request again later.
💬 No message received
1. Page-to-Page messages
When a Page sends a message to another Page, META currently does not provide corresponding events, so it is normal for the system not to receive the message. This means when a Page attempts to send a message to another Page, the system will not trigger related events to handle those messages.
2. Facebook native automation flow
When a customer's message is triggered by Facebook's automation flow (such as collecting leads via an ad post), these messages are handled by Facebook first and therefore cannot directly enter FIRST LINE.
It is recommended to check the source of bot messages in the customer's conversation:
Check whether the message was sent by the FIRST LINE system: If the message was not sent by FIRST LINE, it is very likely handled by Facebook automation or another third-party service.
Wait for the flow to finish: After the customer completes Facebook's automation flow, subsequent messages may then be received by third-party systems.
3. Using other third-party systems or services simultaneously
If you are using multiple third-party systems or services, ensure only one service is receiving the Webhook at a time to avoid messages being delivered to other systems and causing FIRST LINE to miss messages.
If you are using multiple third-party services to receive messages simultaneously, remove the extra services or manage them according to the following settings:
Manage Page settings: Switch to Page identity, click the avatar in the top right, select "Settings & Privacy", then click "Settings".
Page settings: In the left sidebar select "Page Settings", then click "Advanced Messaging".
App settings: On the right find the "View" button, click to enter, find "App Settings - Handover Protocol", then set the "Messenger Receiver" on the right to "FIRST LINE".
4. Meta missed Webhook messages
Since FIRST LINE integrated the Facebook Messenger channel, we have found that in very rare cases Meta failed to correctly deliver messages or information to third-party services. This means when customers send messages, Meta sometimes did not notify other services, or the messages lacked some field information, causing the system to not display the message.
According tothe official developer forum other users' reported issues and cross-checks with the responsible internal teams, we found this situation to be a recurring phenomenon. At various times some community users raised this problem, and unfortunately Meta did not provide much explanation. Sometimes they only stated it had been fixed.
In response to this situation, our team members are actively strengthening the recording of information from Meta to cope with possible future official anomalies and adjustments. If you find you have encountered this situation, please inform us of the timing of the customer's message and other relevant information; we will help confirm whether it matches this scenario.
Other
1. Customer nickname shows as Guest
When a customer initiates via Facebook or speaks for the first time, the system tries to obtain customer-related information, including nicknames. However, in some cases due to Facebook limitations it may not be possible to obtain complete information, resulting in showing guest identity. These situations include:
The user opened a conversation via a checkbox plugin and did not reply to messages on Messenger.
The user interacted with Messenger message ads before replying to messages on Messenger.
Profile information retrieval is not supported for Messenger accounts created with a phone number.
...and other Facebook limitations that may affect collection of user information. The system will still try to provide as much information as possible where feasible to assist in providing more personalized service.
2. Guest plus number name appears in conversation
If some customers on your Page show as “Guest” followed by four digits, e.g. Guest 6521, Guest 9527, it means you have enabled the Page message "Guest mode." In Guest mode conversations are time-limited, and when the customer presses "End Chat" the conversation closes and agents cannot reply again.
3. The agent who linked FIRST LINE with the Facebook Page has left
Suppose the original admin Kevin linked FIRST LINE with your Facebook Page. If Kevin has left, you can remove Kevin's admin permissions from the Facebook Page.
When removing the administrator's permissions, the connection between FIRST LINE and Messenger will fail because Kevin's access token is being used.
In that case you need to reauthorize FIRST LINE with Messenger following the steps above.
4. Types of message tags
Human agent Human Agent
Messages from a human agent replying to the user within 7 days after receiving a user message. This feature is allowed for situations where the user's issue cannot be resolved during the standard messaging window and human support is required, for example businesses closed on weekends or issues that take more than 24 hours to resolve.
Replies to issues that take more than 24 hours to resolve, or messages during weekends or long holidays when operating.
Event updates Confirmed_Event_Updat
Confirm a user's booked event, remind the user of an upcoming event, and notify the user of new arrangements for the schedule.
Event notifications or booking confirmations, event or booking reminders, event or booking cancellations or status changes.
Order updates Post_Purchase_Update
Used to confirm payment status, send invoices or receipts, shipping status, and handle exceptions.
Shipment status notifications, purchase shipping notices, order-related changes (such as card issues, order cancellations, etc.).
Account update notificationAccount_Update
Notifications include application information changes, suspicious activity alerts, job status changes, etc.
Account activity notifications, user profile change notifications.
Advanced removal
Go to the linked Facebook Page and click "Settings", then go to the "Advanced Messaging" section.
Click the app settings button linked to "FIRST LINE" to remove it.
After removal, reauthorize the Facebook Page or Instagram business account linkage following the above steps.
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