1. Could you try accessing different folder in email server and still the same issue ?
2. Are some of the messages are being processed for some time even after these exceptions started printing in logs and before email listener goes down?
Below could be the reason for this issue:
At times the folder on the email server can have an issue and decide to close the folder. The Email listener is not anticipating that the folder can be closed and is trying to process email. Even after getting the FolderClosedException the email listener continues trying and exceptions are logged as until the folder is reopened emails will not be able to be read successfully. On next run the folder will be reopened and processing of the email will happen successfully.
Can you please check with your email server team for any useful information.
What do you mean by “even restart of listener doesn't help”? Do you just mean that the exceptions occur even after the listener is restarted?
What mail server you are using? Is it Office 365 by any chance? Is it an on-premise server such as exchange which you have control over?
How many emails do you have each listener set to process in each run?
The best way to avoid this problem is to limit each listener to as few emails as possible. Start out by setting each listener to process only 1 email per run, and ensure each listener is only on one node and only running one thread, and see if that reduced the incidence of the problem.