There are a few potential reasons why a Facebook message may be sent but not delivered:
Network Issues
One of the most common reasons a Facebook message might fail to deliver is due to network issues. If the sender has a poor internet connection or the recipient’s connection drops while the message is sending, this can interrupt the delivery process. The message may remain stuck in Facebook’s servers without reaching the intended recipient. As soon as the network connectivity improves, the pending messages should go through.
Recipient Privacy Settings
Facebook allows users to control who can send them messages. If the recipient has adjusted their privacy settings to limit messages to friends only, and the sender is not Facebook friends with the recipient, the message will not be delivered. The sender would receive a notice that the message could not be sent due to the recipient’s settings.
Recipient Has Sender Blocked
If the recipient has blocked the sender, any messages sent by the blocked user will not get delivered to the recipient. The blocked sender will not receive any indication that their messages were not received. The messages will simply be discarded by Facebook and not sent to the recipient.
Recipient Deactivated Facebook Account
When a Facebook user deactivates their account, they will stop receiving any new messages sent to them on the platform. Any pending messages sent before deactivation would still be received. But messages sent after they deactivated will be unable to deliver and the sender will get a notice that the account is unavailable.
Facebook Banned the Sender
If Facebook has banned the sender’s account due to violations of policies, they may be unable to send any new messages. Existing messages in the inbox remain accessible. But any new outgoing messages from a banned account will be blocked from delivery.
Facebook Glitches
Very rarely, technical glitches on Facebook’s servers could also lead to message delivery failures. Complex systems like Facebook sometimes encounter temporary bugs that disrupt normal functioning. Messages getting stuck before reaching recipient could be an indication of such backend errors. Usually gets resolved on its own in a short time.
When Does the Sender Get Notified of Delivery Failure?
The sender gets notified almost instantly if the message could not be delivered for reasons such as recipient privacy settings or the account being unavailable.
For failures due to network errors or temporary glitches, senders may not get notified immediately. The system will keep retrying to deliver the stuck messages for some time. If delivery continues to fail beyond 24-48 hours, the sender would get notified that the message remains undelivered.
What Happens When a Message Fails to Deliver?
Message Remains in Sender’s Outbox
The undelivered message continues to show in the sender’s Facebook outbox with a red exclamation indicator that it failed to send. The sender can try resending it manually.
Sender Given Failure Reason
As mentioned before, in most cases Facebook informs the sender why delivery failed – such as account unavailable, recipient settings restriction, etc. This helps them understand what went wrong.
Message Discarded after 30 Days
If a pending message remains stuck for over 30 days despite resend attempts, Facebook will eventually discard it from the server. The sender will get a notification that the message has expired due to a delivery issue.
No Notification for Blocked Sender
The only situation where senders get no indication of failure is when recipients have blocked them. Facebook does not alert blocked senders to protect the recipient’s privacy.
Troubleshooting Tips for Senders
Check Network Connection
Make sure you have an active internet connection. Try switching wifi networks or toggle cellular data if needed. See if you can load Facebook properly.
Update Facebook App
An outdated version of the Facebook app can cause messaging problems sometimes. Update the app to eliminate any software bugs.
Try Resending the Message
Attempting to resend a stuck message often resolves temporary glitches. Wait a while before retrying if needed.
Check if Recipient Account Exists
Search for the recipient’s profile to confirm they still have an active Facebook account and have not deactivated it.
Review Blocked Senders
Check your blocked senders list under settings to see if you accidentally blocked the recipient causing messages to fail.
Contact Recipient Outside Facebook
If you know the recipient outside Facebook, try contacting them through another means like phone or email to troubleshoot the issue.
Contact Facebook Support
As a last resort, report the persistent message delivery failure to Facebook support if you cannot resolve it yourself.
Preventing Message Delivery Failures
Confirm Recipient Details
Double check you have the exact correct spelling of the recipient’s full name and account username before hitting send.
Review Privacy Settings
Check your privacy settings occasionally to ensure you have messaging enabled for broader access and haven’t limited too much.
Unblock Contacts You Want to Receive Messages From
Periodically review your blocked senders list and unblock anyone you want to reconnect with.
Don’t Deactivate Account Too Often
Frequently deactivating and reactivating your Facebook account can lead to messages failing to deliver during deactivated periods.
Conclusion
Facebook message delivery can fail due to various reasons ranging from network errors, account settings, block lists to platform bugs. Senders get notified immediately in most cases but messages stuck for over 30 days eventually expire. Following some basic troubleshooting tips like resending messages, checking connections, and reviewing settings can help resolve many delivery issues. Being mindful of your account status and settings helps minimize problems. Overall, Facebook’s messaging system is robust but occasional hiccups leading to undelivered messages are not uncommon.