Cannot send an invitation to another integrator

Hi

I have written a project for another registered integrator, and the easiest way to test this is to add the project to the cloud, add a trial license, and invite the integrator so he can download and test the project. After the project is handed over, he will only then add it to their cloud account.

But I get this error:

(I have changed the above to my email in the screenshot to protect the integrator's privacy)

Please change so I can send an invitation to another registered integrator