I've ran into this issue maybe twice in years and I'm always using that for websites. I'm having a feeling that issue is a bit overblown.

I just add . in arbitrary places to distinguish sources. Since there's no telling what dots a gmail user thinks are a significant part of their address.. (plus I have seen fail and late enough to be a pain, but due to http parameter escaping, etc, rather than intentional fitering.)

That's why I use "." as the separator.

Now try using an email from a domain name with more that 3 letters in the TLD.

Almost no one considers that a valid address.

So if I bought my “name.rocks” I’ll have trouble using that as an email? I was looking forward to “firstname@lastname.rocks” and I never even considered it would be a problem. I’m disappointed

I have something similar - I haven't had many problems with the not being accepted online. The few times I've had issues are with old point-of-sales or appointment booking systems.

Yes. I'd say way more than half of sites won't accept that as a valid email.

And you'll be flagged for fraud as well.

It's very frustrating.

I have a .help domain for handing out to services and it works without issue.