Comment by reify

I personally do not visit any site with a captcha.

I dont play silly games.

However, in the past I have noticed that some addons prevent the completion and create a continual loop.

disable each addon if you use them one at a time to see if that makes a difference.

you dont say which OS you are using.

If you are not tech minded install bleachbit and run that to clear out all the hidden rubbish in .cache etc.