telnet pop3 user 'err protocol error'

antonioking used Ask the Experts™
I am seeing the following error after succesfully connecting on Port 110 to our exchange server using TELNET and typing in USER journal
"ERR protocol error"

The users username is "journal"
If I try other usernames it works fine... what could be the issue?
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Do you have proper SSL Certificates on Server and the client trusting those certifiate authority?

One of the reasons for the error is certificates not configured properly. If you are using a custom application, you can turn off SSL for POP using the following command.

Set-POPSettings -LoginText PlainTextLogin

After executing this command, please restart POP3 service.


Hi, turned out simply restarting the pop3 service resolved my issue.

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