An user has changed their password in POA Control Panel. After that, user cannot log in to their Exchange mailbox using Outlook or OWA with the new password.
Password change was not yet completed for user in Active Directory or user's password was changed manually in AD.
1. For each Exchange mailbox POA creates user account in Active Directory. When user changes their password in POA Control Panel, a task 'Set properties for AD entity '<user name>' of type 'UserAccount' (entity_id: <POA user ID>)' is being scheduled by POA.
Check failed/unprocessed tasks for the problem user in POA Task Manager - filter tasks by the problem user name or ID. If there is a failed or unprocessed task, find a problem that does not allow the task to complete and fix it, re-run task after that.