Hi Marius,
Thank you for querying in his forum.
I go through the post carefully. It seems like you cannot view Microsoft transcript as the Transcript page shows a blank page. Sorry for the inconvenience caused at your end.
Considering the issue is related to Microsoft Transcript page and the current forum category is mainly focused on Microsoft 365 Education plans related issues and queries. To make sure you get the dedicated support, I sincerely recommend you post the question in Microsoft Certification Community, it is the specific channel handling this kind of queries, members and engineers in that community have permission and more resource to help you further investigate the issue. I hope your question can be addressed by experienced assistance.
In the meanwhile, I wish to try my best to help you. I searched a lot for the issue and found similar threads below. You may refer to them.
Unable to view transcript page. - Training, Certification, and Program Support (microsoft.com)
As it my need to collect your profile information to check the issue, I still recommend you post question in the community I mentioned above, the engineers will provide specific suggestions based on the specific scenario on your side.
Thanks for your patience and understanding. Hope you have a nice day!
Best regards,
Tina