Cannot add User email to access an App because reCAPTCHA service not available

At 11:30 AM Eastern Time, when I click “I’m not a robot”, I get this message :

“Could not connect to the reCAPTCHA service.
Please check your internet connection and reload to get a reCAPTCHA challenge.”

Please contact for help with this.

I found out that the Captcha worked in App A but not in App B. I tried to reload the App Editor page several times but it still did not work in App B. I eventually closed App B’s Browser tab, then opened the App Editor again in a new tab and the Captcha worked. I guess it was a browser related (i.e. cache) problem.