[Springtime]

Yup. And Yandex is one of the only free email services left that doesn't require a phone number to register yet they stuck me with a lockout on the account weeks later (still haven't bothered to re-activate the account yet).

Not to mention that I created both a custom question and answer with randomly generated strings that couldn't possibly have been known by anyone else, which they confirmed as correct during the lockout and still are demanding a phone number to 'verify'. I mean, really now, how on earth would giving any random phone number further verify I'm the account holder when I already know the correct randomly generated password, secret question and secret answer.

Gmail has similarly locked out various accounts with this despite no actual suspicious activity and having a completely unique password. It's a transparent effort by all these companies to gather more user details.

[st1ck]

https://cock.li/ doesn't require phone number (you can also choose other domain name)

[pas]

ProtonMail doesn't require a phone number either for registration.