I have the problem that this error message appears when I add my DNS entry for my mail server.
Despite the error message the mail system runs fine, it receives emails and can also send some, but runs on a different port, but that doesn’t seem to be a problem.
However, the problem that occurs is that the mail system takes a long time to load, guessing 10/20 seconds until the page is reachable.
I tried to redirect my webserver to the old nameserver for test purposes, there the page loads fast without problems.
I suspect that the long loading time is due to this error and would like to fix it, but do not know how.
I hope you can help me! Thanks