Everyone has the same error as the problem is not related to geo-blocking, the message is just a generic video for content not found.
The issue is due to the fact that to obtain the actual URL to the mp4 video file the addon makes this query:
http://cdnsel01.mediaset.net/GetCdn2018....ormat=json
where 751387 is the id of the episode you want to play (that's a quarto grado episode from Sept 2017.
The response provides the URL to the video
{"state":"OK","code":"200","videoList":["http://vod06.msf.ticdn.it/farmunica/2017/09/92726_15e63b1c43da2f/15e63b1c43da2f-20_0.mp4"]}
Since Friday April 13th they changed something and this is not working anymore for any program and any new episode, for example 831002 is quarto grado episode from Friday 13th
http://cdnsel01.mediaset.net/GetCdn2018....ormat=json
This is the response:
{"state":"OK","code":"200","videoList":["http://vod06.msf.ticdn.it/error/Not_Available.mp4"]}
A different id must be used and it can be found in the shtml file specific to each episode on this line:
<article data-node="video" data-type="video" data-cid="831002" data-rid="831002" data-format="" data-codf="F308790901001201">
the data-codf field is the id to be used in the query above and in fact:
http://cdnsel01.mediaset.net/GetCdn2018....ormat=json
returns:
{"state":"OK","code":"200","videoList":["http://vod06.msf.ticdn.it/farmunica/2018/04/191535_162c130caef965/162c130caef965-20_0.mp4"]}
I applied a workaround that requires changing 4 lines on the mediaset.py file, it's super inefficient as I'm not a developer, so maybe someone can fix this in a more elegant manner.