When MainWP is syncing and you have a site with an expired certificate, it’s not possible to continu syncing if you have “Verify SSL certificate” enabled in Advanced Settings. Which makes totally sense.
When disabling this checking in the Advanced Settings it’s able to connect with the MainWP Child.
Which got me courious about how this connection is established between MainWP and MainWP Child. Is this an independant encrypted connection between the two or does it fall back to an unencrypted session?