Upgrade not possible, Tax number is not accepted

Hi, I want to do an upgrade and Zoom is asking me for my tax number. Unfortunately it doesnt accept my existing tax number. It always says it would not be excisting…

Then I tried to use a personal account instead, there it is needed also (which doesnt make sense to me).

I have 2 tax numbers, Zoom doesnt like them all… Any suggestions how I can buy an upgrade???
Thanx