Links to Relevant Wiki Articles(s):
You should first confirm that https://www.recaptcha.net/recaptcha/ isn't blocked.
Unfortunately, the reCAPTCHA may be difficult, even for humans. Since it is developed and supported by a 3rd party (not the Scratch Team), we have limited control over its behavior. You may have to attempt the reCAPTCHA several times in order to log in. However, if you’re using the correct password consistently, then you shouldn’t have to interact with the reCAPTCHA on a regular basis.