Please make sure to update your JDownloader to latest available version.
You
have to install the MyJDownloader Browser Extension in order to solve RecaptchaV2 in Browser.
You can download from here,
https://my.jdownloader.org/apps/
A
MyJDownloader account is NOT required for the RecaptchaV2 handling!
At the moment only Firefox, Chrome and Opera are supported!
IE, Edge and Safari do not (yet) support webextensions!