I made sure my DNS records are valid in case they are checked. There might also be a chance that the "newer"/longer top level domains are not supported by the validator. Because to be fair: This undetected stone-age-issue would be pretty reasonable for a serious software with serious businesses having only serious TLDs.
I now use my private ".com" address and only found the option to change my >contact< address to "email@example.com".
No "account-address" fix required on my side. I am just happy to test things for a very good reason. Best Regards, Thomas