When I attempt to edit or duplicate a TinkerCAD design the page switches to display a centralised coloured box, but doesn't progress to the actual edit screen. I've tried waiting for an extended period but it seems that the web site has got stuck in a loop.
This has been hapening for more than 24 hours.
Alo, I am using Kaspersky AV, though I haven't looked into that. I'veused Kaspersky without problemfor several years, so that's not new.
It not Kaspersky I disable it and the page not loading
After spending some time researching this, I can confidently report that I now have this working!
I took on board comments which had been made about Kaspersky,and started by re-enabling that FireFox plug in (I had disabled it and that hadn't fixed the problem). I then disabled Kaspersky from protecting security enabled web sites (which TinkerCAD is as it uses an HTTPS URL), then configured the Kaspersky proxy server settng for this plug-in, and was then able to edit TinkerCAD designs as normal.
Previously I had defined Kaspersky to auto-detect proxy settings - I changed that to explictly define the proxy server.
I'm not sure if it was removing protection for HTTPS sites or defining the proxy settings which resolved the problem, but clearly at least one of those had an effect. I'm not sure I like the idea of removing protection for HTTPS sites so I'm going to look into this further.
I would therefore encourage anyone who might suffer from this problem to take a close look at their anti-virus configuration. There's something about the TinkerCAD web site which impacts anti-virus monitoring.