I signed up for a Unitymedia contract using Check24 and shortly afterwards I received an email asking me to verify my email. When I clicked on the link it asks for my birth date, which I enetered corretly, however the form rejects it saying "Das hat leider nicht geklappt! Gib bitte das Geburtsdatum des Vertragsinhabers ein".
This has been going on for days now. I even received a reminder that I need to verify my email.