Today I sent such an email to Jetpack – maybe it will be useful in this case as well.
I don’t know for sure (because I didn’t receive any feedback from Jetpack on my emails) whether the problem was also on the Jetpack side (wordpress.com) or only on the side of my hosting and the configuration of my blog.
After six days, the lack of connection to WordPress.com was diagnosed and the connection was restored.
It is probably worth adding to your pages about connection problems the issue of checking and at least temporarily disabling the Web Application Firewall (WAF) if something like this is installed on the users’ hosting.
In my case, the problem became even more complicated – it was described by the administrator as follows:
“If the .htaccess entry regarding WAF is commented out, WAF will be disabled, even though it may be visible as enabled in the DA panel.
Changes in the panel regarding WAF should be reflected in entry in .htaccess, but sometimes this does not happen,
so it is worth checking whether the entry in .htaccess is correct (commented or not).”
I will also add that now on my website with xmlrpc.php
with WAF enabled I get the message:
XML-RPC server accepts POST requests only.
And from the website: https://jptools.wordpress.com/debug/
I have a message:
Everything looks great!
All tests have passed for blog.tripsoverpoland.pl and your Jetpack powered site looks good to go!
But in the debugger in Chrome I see this:
GET … xmlrpc.php 405 (Method Not Allowed)
So it would be worth adding a small addition to the xmlrpc.php topic in your guide.
I hope this helps with diagnosis.