3CX SMTP server returns: AthenticationInvalidCredentials: 5.7.0 Denied error

[sip.bg]

Newly installed 3CX standard instance.
Testing email server returns: AthenticationInvalidCredentials: 5.7.0 Denied error.

Any clue ?

 

[YiannisH_3CX]

Hello @sip.bg

This is caused when the system was is authenticating to the ERP with one public IP and the SMTP request comes from a different public IP address. If the system is set to static public IP the switch it to dynamic and restart services. Wait for a bit and then try the test again. If this fails then send me a personal message with your licence key so i can look into the issue

 

[sip.bg]

Hi Yiannis,
thanks for reply, I forwarded your answer to customer and I'm awaiting his response.