This is the place to look if you are trying to trouble shoot a problem and you have received or have access to a specific error message or error code. If instead your problem is that something you think is set up correctly is not working then the best place to look would be the not working as expected page.
Note that many error messages are from your Internet provider, and are just being reported by VPOP3 - in that case you should contact your Internet provider for help. Other error messages contain descriptive text to try to help.
Note that Outlook is not our software, and there are many errors which Outlook will generate which are nothing to do with the VPOP3 server, so these entries are here purely for convenience.