bot on messanger stop responding

Please be aware that you are posting on an Italian forum. However, your post's content is in English rather than Italian. As a result, I will reply to you with information in English.

Hi @rita conforzi,  

Welcome to Microsoft Q&A forum. 

Regarding the reported issue where the virtual agent on Messenger has stopped responding after a year of operation, please provide answers to the following questions to help scope the technical failure: 

1. Is the bot failing to respond to all users, or are only specific individuals or regions affected? 
2. When a user sends a message, does the status in the Facebook Page Inbox show as delivered or seen, or does it remain as sent only? 
3. Have there been any recent changes to the Facebook Page administrative roles or the Meta developer app permissions? 
4. Does the bot continue to function and respond correctly when tested directly within the internal test pane? 
5. Are there any specific error codes or warnings appearing in the session logs or environment analytics? 

The issue may happen from vary causes for need to troubleshoot. Please perform the following three troubleshooting steps in the meantime: 

1. Step 1: Validate the Facebook App and Page Access Token
   • Navigate to the Meta for Developers portal to ensure the application is active and the security tokens have not expired.
   • These tokens often require periodic renewal to maintain the communication bridge between the virtual agent and the Messenger platform. 
2. Step 2: Refresh the Messenger Channel Connection  
   • Access the channel settings within the bot configuration portal.
   • If the connection appears stale or disconnected, disconnect and then reconnect the Facebook channel to re-establish the authentication link. 
3. Step 3: Verify Environment and License Status  
   • Check the administration center to confirm that the environment hosting the bot is active and has not reached its data capacity.
   • Additionally, verify that the account used for the connection still has the required licenses assigned and that no service interruptions are reported. 

Kindly update the outcome to let me further check if the problem persists.