It is also not possible to add a new account as a domain administrator.

+1

Good morning and thanks for getting this reported. I have not yet been able to reproduce the API error but I do see the error when creating new users as a domain administrator. I'll get this written up for development now.

I just wanted to follow up with you on this to let you know we were able to find a fix for these user creation issues and will have a fix in our next public release build.