Outlook and Gmx not working

X-Notifier 3.5.1 Firefox addon: Outlook do not work; the account is grayed

You -probably- need to manually log into your outlook.com account and answer a prompt... I just checked and after I answered it, X-Notifier was able to check the account for new email again.

The prompt says:

                     We're updating the terms for your account

We're updating the terms of use and privacy statement for your account. Thanks for using Microsoft services!
Learn more about this change.   

(It's about their "revised Microsoft Services Agreement (MSA) and our new privacy statement".)

So... you can right-click on the X-Notifier 'envelope' icon and click your outlook.com account to go to your account and get the prompt and answer it, or... open a new tab manually, and go to outlook.com and log in... answer the prompt.  After the prompt is taken care of, X-Notifier can auto-login and check for new email.

I can't say why GMX may have trouble, but try logging in manually.