550-5.7.1 Our system has detected that this message does not meet IPv6 sending guidelines regarding PTR records and authentication
I think I finally got this issue fixed. Warning: 550-5.7.1 Our system has detected that this message does not meet IPv6 sending guidelines regarding PTR records and authentication. Please review 550-5.7.1 I first mentioned the problem with the IPv6 warning in this thread. And then I mentioned it again here. And I had thought it […]