Logon to my account only works after a password reset

Hi together,

does anyone has an idea whats going on? After a couple of days ChatGPT is always blocking my sign-ins telling me the credentials are wrong. The only way to get access again is, to reset my PW…even to the old one is fine. Since the password reset is only working through email, i would have seen if the password has been changed by 3rd party or so.

Is there any other known reason for blocking sign-ins? Like many failed ones, or account sharing, or so?