Hi ED •,
Welcome to Microsoft Q&A forum.
I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to "Accept " the answer.
Key vault key was expired hence the Server was inaccessible.
Thank you. Have a good day.