Windows : Exchange POP3 “Your e-mail Server Rejected Your User Name”

By | February 12, 2017

If you encountered the following error trying to connect to a POP3 account on your Microsoft Exchange mail server, this might indicate the following issues :

– The POP3 protocol isn’t enabled for this account ;
– The login type you are trying to use isn’t currently supported by the server.

This usually happen when trying to use a non-SSL connection. By default, Exchange will only accept encrypted connections. If you know what you are doing and would like to allow non-encrypted connection, simply do the following :

Warning! Applying the command(s) suggested below mean that users can authenticate sending their active directory password in clear text.

1. Open the Microsoft Exchange Shell Console with elevated privileges.

2. Enter the following command to allow unencrypted login :

Set-PopSettings -LoginType PlainTextLogin

NOTE : The command above signify that encryption isn’t required for authentication on port 110.

Alternatively, you can set the following :

Set-PopSettings -LoginType PlainTextAuthentication

NOTE : The command above signify that encryption isn’t required for authentication on port 110 but basic authentication is only permitted on port that use TLS or SSL encryption.

The default setting is the following :

Set-PopSettings -LoginType SecureLogin

The POP3 Exchange service must be restarted after applying any of these parameters.