Mail rainloop

Hello i cant send ant and get emails i got rhis error

This is the mail system at host

I’m sorry to have to inform you that your message could not
be delivered to one or more recipients. It’s attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

               The mail system host[2a00:1450:400c:c0a::1b] said: 550-5.7.1
[2a05:7cc0:0:185:34:52:179:1] Our system has detected that this 550-5.7.1
message does not meet IPv6 sending guidelines regarding PTR records
550-5.7.1 and authentication. Please review 550-5.7.1
Prevent mail to Gmail users from being blocked or sent to spam - Gmail Help for more information 550
5.7.1 . i14si3565292wru.380 - gsmtp (in reply to end of DATA command)

The same thing happens to me, it seems that Cyberpanel has some problems with IPv6 connections.

Let’s see if some administrator answers us

Having the same problems here are well. Did anyone find a solution?

I think its due to rDNS, so you can do either of the following 3 methods to fix it

  1. please add PTR record and try to send the email.

  2. or you can modify the of postfix and make outgoing IP bind to IPv4 only

  3. or disable IPv6 in server either by disabling ipv6 address or by editing /etc/sysctl.conf

how to add PTR record to ipv6 … i am totally confused

i am getting the same message above whenever i am trying to send email to Gmail account … sending emails works perfectly

Try to connect your cyberpanel to and then use the Email debugger to reset your mailserver. This may solve your config related issues.