Hey @bob-simpson-0,
Indeed to connect a domain to a project the project must have an active subscription
(you can't connect a domain to a free project)

About the non transferable domain my guess is we don't support that particular domain extension. You can still connect it to your project as an external domain

Hey @nazem-samad
can you check here if your VAT number is correct?

https://ec.europa.eu/taxation_customs/vies/#/vat-validation

If not our system will reject it and apply VAT

Hey @elsa-maman,
Disable SSL then wait 1H then reenable it, this will solve your issue