We have the same problem and it is not just outbox problem but also mail receiving delay problem.
We found that this problem is starting from outlook version 16.0.17231.20182.
We have to downgrade outlook back to "16.0.17126.20132" in order to temporary adjust this problem or change to use Outlook connector.
Outlook client keep updating, the compatibility between Zimbra and Outlook looks difficult to maintain and facing high risks of facing problem.
Just like last month, Outlook connector faced problem of sending blank email after Outlook upgraded and need to took weeks to solve the problem.
We found that this problem is starting from outlook version 16.0.17231.20182.
We have to downgrade outlook back to "16.0.17126.20132" in order to temporary adjust this problem or change to use Outlook connector.
Outlook client keep updating, the compatibility between Zimbra and Outlook looks difficult to maintain and facing high risks of facing problem.
Just like last month, Outlook connector faced problem of sending blank email after Outlook upgraded and need to took weeks to solve the problem.
Statistics: Posted by tanyhui — Mon Feb 19, 2024 8:31 am