Troubleshooting Outlook with Zimbra Connector

If a user’s mailbox cannot receive new mail, becomes out-of-sync, or the .zdb file becomes corrupted, try creating another profile to see if the problem persists.

In some cases, it might be necessary to uninstall ZCO, delete the profile and .zdb, and start over.

See these articles:
https://wiki.zimbra.com/wiki/Howto_manually_uninstall_ZCO/ZCB
https://wiki.zimbra.com/wiki/Creating_New_Profile_for_ZCS_Connector_for_Outlook