Emails will not arrive to t-mobile.de email addresses. Please use other emails provider such as gmail, outlook, yahoo mail etc...
Please use other emails provider.
If you're still not receiving the verification code email, try these steps:
Check email Accuracy: make sure the email address is correct.
Inspect all Folders: look in spam, junk, or promotions folders.
Wait a bit: emails can be delayed. Give it a few minutes.
Refresh/logout: refresh your email or log out and back in.
Check filters: ensure email filters aren't blocking the email.
Email server status: check for any issues with your email service.
Try another email: if none of these steps work, it might be due to your email provider not accepting these types of emails. Consider using a different email address.
A little patience and checking these can often solve the problem.