The error: The action cannot be completed. The name cannot be matched to a name in the address list that may appear when a user is trying to connect Outlook to multiple mailboxes hosted on the same server.
Such an issue is usually being caused by Windows Credential Manager which stores the cached credentials for Outlook accounts.
To resolve the issue:
- Close Outlook
- Open Windows Control Panel > Credential Manager > Windows Credentials
- Delete all entries under Windows Credentials associated with your email account
- Open Windows Control Panel > Mail. Try to add a new mailbox to the list of the mailboxes for the existing Outlook profile
- Enter passwords for all mailboxes as the pop-up window appears. Pay attention to which address is mentioned in the pop-up window header
Read the Knowledge Base article How Do I Save My Outlook Password for more information