On the server mxavas.forpsi.com, for safety reasons the MX records of the domain of the recipient are checked. At least one MX record has to show to mxavas.forpsi.com or to the IP 81.2.195.200. In other case, the email is rejected, although the domain exists on this mailserver mxavas.forpsi.com. The error:
5.0.0 smtp; 550 5.1.1 gaui1p0062iCB6t01auiH0 Sorry, relay access denied, see https://support.forpsi.com/KB/a3406
This situation can occur, when you have transfered your email services to Forpsi and you have changed the MX record of your domain. It takes some time till new MX record is gotten on all cache DNS servers.
If you are going to transfer your email services to Forpsi, or you got the error above, contact us with
authorized ticket. We will set for your domain an exception from this check.
Note: MX records are also checked in case of forwarded emails, autoreplies and error messages. If the target domain has all MX records showing to other mailservers, the messages are delivered by MX records, although the target domain exists on the server mxavas.forpsi.com.