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cPanel Exim Error 550 - Please turn on SMTP Authentication on your mail client

Written by: on 25 March 2021 11:30 AM 25 March 2021 11:30 AM
Conditions: VPS with cPanel installed, Exim in use as SMTP server

Symptoms: Exim mail log is full of following messages:
550-Please turn on SMTP Authentication in your mail client.

550-your.mail.domain [xx.xx.xx.xx]:yyyy is not permitted to relay

550 through this server without authentication.

However your mail client 100% has SMTP Authentication enabled in settings (this is important).

Possible cause: Exim changed the list of allowed SSL/TLS ciphers because of update

Solution: Login to WHM, openĀ WHM > Service Configuration > Exim Configuration Manager and set "Allow weak SSL/TLS ciphers" to On.

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