Licensing error Trados Studio 2021 with SDL License Server

When I enter the license code I get "one or several errors have ocurred".

If I try it again I get the error 999 license number cannot be 1 or 0.

I checked and the license is registered a used now.

But it does not appear in the License Server.

I have actually installed a Studio trial version that has expired.

I have no idea how to fix this.