Having scoured the internet for a recent issue, including this stie, explanations of how to fix 'there was a glitch, try again in a few minutes' didnt resolve my ongoing issue. I have a total of four speakers, one mini and three of the older home type. All were showing this issue.
Nothing had changed in regard to my BT router, but i've now confident that the issue is with the original setup i did using the 5ghz channel of the router rather than the 2.4ghz.
I re-installed all of the speakers and they now all work perfectly, whenever i ask a question, i get a response.
I'm sorry you had to go through that and we really appreciate you taking your time showing what you did in the Community and how you resolved it. It looks like we can consider this one complete, so I will lock the thread in 24 hours unless I can help out with anything else.