Both test-pages (Test and Test-mVm) are working fine, back and front.
I tested some other existing pages, sometimes it saves, sometimes it keeps on spinning and sometimes i get this error 'request failed with status code 503' which means (I think) that it looks like the connection with the server is lost.
Especially the 4 Homepages are giving problems with the Save button. It might be the Slideshow addon.
The Homepage (default) page creates a saving problem all the time.
It looks like if you create a new page there is no problem.