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telnet pop3 user 'err protocol error'

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?
1 Solution

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

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