What is wrong with my email address on Twitch?

The following problem occurred while registering on Twitch:

Question: does Twitch not accept the gmx.de mail provider? What do I have to do so that the registration is completed successfully.

For the trolls, yes, the screenshot has been edited to be more anonymous. That is not relevant to the question. The nickname has been recognized as available.

Well the email already exists, is already in use.

Problem solved. I already have an account there