This domain is being caught as a permutation of another domain on our high-value domain blacklist. I’ve submitted a correction to the policy that should allow you to register mail.webmoney.eu but it will take some time to activate this in production. I will update this thread when it has happened (Potentially as soon as Thursday, Nov 3rd).
Thank you for the answer and cooperation. I hope you will manage to solve this problem as quick as possible.
Wait for the positive result. Thank you once more.