"For Signature" not working

My Adobe sign has stopped working. Last time I used it was a week or two ago. I have two machines, a desktop and a laptop, and it has stopped working on both.

Strangely, I can't access the signature functionality through either the web interface or AdobeDC.

When I send any document to "For Signature" in DC it either stalls on the upload (18% or 60%) usually and just sits there. Or the upload completes and I just get a blank page with the faint text "The thumbnail could not be loaded".

If I use a web browser (Edge, IE or FIrefox - yes, cleaned cache etc) then I can see "For Viewing and For review" in the left menu and a few seconds after the page loads "For Signature" appears. However, I can't access the signature functionality at all. I get a "Loading Adobe Sign" spinner, or a blank page.

I have also tried on a VM and it's the same.

If I VPN to another country (hence, change my IP and geolocation) it seems to work.

I really shouldn't have to do that to use the service.

I've had an Adobe technician from support remote to my PC and give up telling me they can't support the web based service. They wanted to install a shed load of more Adobe software to troubleshoot DC which I asked them no to.

If anyone has any ideas I'd be grateful.

Thanks in advance

Andrew