Hi,
Can you share the Debug log of your test mail here?
It would better help us in investigation of the issue.
Thanks
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Debugging Output :
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220 mail.trisect.uk ESMTP Postfix
EHLO localhost
250-mail.trisect.uk
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250 SMTPUTF8
STARTTLS
220 2.0.0 Ready to start TLS
EHLO localhost
250-mail.trisect.uk
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-AUTH CRAM-MD5
250-AUTH=CRAM-MD5
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250 SMTPUTF8
AUTH CRAM-MD5
334 PDI2MDA3NTY0Nzg5MzkwNTQuMTUxMzg2NjgzOEB0aGFsbGl1bT4=
ZGFubnlAdHJpc2VjdC51ayA0MWE4YWJjMTQ5MDExN2U1MGQ4YzM4OTYwNzBmYzE3OA==
535 5.7.8 Error: authentication failed: PDI2MDA3NTY0Nzg5MzkwNTQuMTUxMzg2NjgzOEB0aGFsbGl1bT4=
Your Web Host provider may have installed a firewall between you and the server.
Contact the admin of the server and ask if they allow outgoing communication on port 25,465,587.
It seems like they are blocking certain traffic. Ask them to open the ports.
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Hi,
You would have to contact with your Server host and ask them to do the following settings:
1. You would need to login into your WHM Panel and under this go to Tweak Settings. Under the Tweak Settings, turn off the option (Restrict outgoing SMTP to root, exim, and mailman (AKA SMTP Tweak)
2. You would need to login into your WHM Panel and under Plugins section, click on the option “ConfigServer Security & Firewall”. After that under the ConfigServer Firewall tab, click on Firewall Configuration option. Under this turn off the options “SMTP_BLOCK” and “SMTP_ALLOWLOCAL”.
We have attached all the screenshots for your help. Please have a look at it.
https://ibb.co/k96oCG
https://ibb.co/eqEKKw
https://ibb.co/djtqRb
https://ibb.co/kgK8CG
https://ibb.co/mQZmzw
Hope that fixes the issue for you!
Thanks