Create A Forum - Support Forums

My forum, globalyou.createaforum.com or
tofort.com is having problem now. When guests are trying to register while using other browser except chrome, this displays:
"Please upgrade to a supported browser to get a reCAPTCHA challenge.
Alternatively if you think you are getting this page in error, please check your internet connection and reload.
Why is this happening to me?
Privacy - Terms"
And they can't register again. Help me out pls.