I have had a look at a couple of similar topics, but no obvious solution is available. I have SSL Insecure Content Fixer installed and it shows everything OK.
Bit out of my wheelhouse here, so any help appreciated!
that is strange. @MattyRob what could be the issue here? could it be due to the cp.net site being down a while ago (now it is back up).
can you go to site health (second tab where site info is) and copy the info pasting them here? they give an outline of the server to see if something might be wrong with it.
This is probably due to poor connection with other sites. Could be firewall or DNS issues on the server.
In Tools > Site Health, is there a passed test called “Can communicate with ClassicPress.net” or does that fail? Does Plugins and Themes get updates notified?
What software are you currently using - WordPress or ClassicPress? And which version?
This could be an issue with old certificates, there is an old fix plugin for this that might be worth a try. You can access it at the link below and there is a good guide there also:
Using WordPress 4.9.22 - which is the last version my site will run in due to theme and plugin conflicts. That will be why the site health is not in the tools I suspect.
So, the api server checks in ClassicPress are https only, if there is an issue in the certificates on the server it won’t work. That plugin I directed you to tries to update the certificates and if that still fails it allows insecure requests for a short period that should then allow the migration.