Thanks for contacting us and I'm sorry for the caused inconvenience. It turns out you have two accounts with the Telerik Platform and one of them is suspended. Please switch and make default your active account and try to create the projects again.
There's a known bug for users who have several accounts with the Telerik Platform and one of them is suspended. This bug prevents us from creating AppBuilder projects for the active accounts. The workaround is the one which I described above. And there's already a fix on its way to the live environment in the next couple of weeks.
Please let us know if this works or not for you.