Reminds me of sites not accepting "+" in an email address, even though it's a completely valid character to use before the "@".
I think in that case it might a matter of length, rather than symbols, but I've never put in the effort to pin down the problem exactly, now that my password manager settings work.
Like, I caught them doing the "ask for FQDN but reject FQDNs" a couple of weeks ago in either Route53 or something immediately adjacent (i.e. where people who know better should have been involved), yesterday SageMaker stopped launching kernels because of a "known issue" (don't worry, it doesn't meet the definition of downtime though), and today I had to diagnose an unresponsive control panel by opening the console and digging up a REST error response that they didn't bother to handle in any way.
Everything about AWS is not merely broken and half-assed, but fractally so, so that even after using a service for years you are still uncovering severe caveats and awkward limitations. Password validation traps fit that pattern to a T.
I do now have a hyphen in my last name which is not accepted everywhere. Some companies accept the hyphen but replace it with a space (some credit cards), some reject the hyphen so I either make it all one word or add my own space.
That's incredibly obtuse of them; what possible reason could they have for doing that?
Essentialy, if your site targeted every age demographic or even had a preference for older and/or less tech savy demographics, how can you prioritize the edge case that <0.00001% of your users has their own lastname.tld vs is entering an incorrect email address.
I agree that it's a huge UX problem - one of the reasons why a lot of online checkout processes have you type your email address in two separate fields, twice. Without some guardrails in place, there is probably a not insignificant number of people who typo their email address in a single field, or type a malformed address, and then complain to customer service or their credit card company when they never receive an emailed invoice.
Worse case scenario, you could use firstname@subdomain.lastname.com. Even something like 1.lastname.com would likely work.
I suppose it depends on your reasons for using your own domain in the first place but having to employ the use of a gmail acount negates a lot of the privacy & security of a personal domain IMO.
I have in the past normalized email addresses per the rules I know specific providers have to help people login. Did I sign up with mike+hn@ or mike+hackernews@?
For example: ycombinator.com@example.com.
Nobody blocks dots in email addresses, although I have had some sites in the past email me using the first part of my email address as my name; it's amusing to open an email from example.com saying "Hi, example.com!"
https://haacked.com/archive/2007/08/21/i-knew-how-to-validat...
For any programmer that's ever tried to validate email addresses it's an eye opener.
Other hosts (e.g. Mailbox.org, the host I'm with now) can support the feature as well, with some configuration.