Schedule a Microsoft Exam

Good morning. I'm using the standard Microsoft "EXAM REGISTRATION PROCESS". At the 3th step I click: "Schedule with Pearson Vue", but at the next step:

This error has been present for a long time (many weeks). I have tried connecting to different computers from different networks with different browsers, but the result is always the same.
I contacted Pearson VUE who responded like this:
"Dear Mauro, Thank you for contacting Pearson VUE. We can not see any issue with your account."

I don't know what to do because no one can help me. Is it a Microsoft problem?

Best regards