Earlier quoted context omitted.
Yup, I feel your pain. One of my emails is @ .com. This fails verification on so many websites it's just comical. I then figured on making a @ .com. Turns out folks mostly validate .com in my experience, which I assume is because of good old mail.com. It's frustrating.
I gave up using mail@ .network because of the significant percentage of sites that refuse the .network TLD. One large financial services provider even told me that their "policy" was to allow 3, 4, or 5 characters as the last part of the domain. So .ninja is A-OK. I pointed out how ludicrous this was, and they told me it was their "policy" again, and that's why Australian Super doesn't have any of my money.
Wow, no country codes? I could understand a restriction dating from before the great expansion of TLDs, but expect it to have a 2 in it.