When I click on the 64bit exe only a light grey empty window (about the size of the Tixati starting Logo ) appear for a couple of seconds, then the program crashes and closes itself with no message at all.

Only a 0 byte (totally empty) txt file is created inside the folder where the portable tixati exe is .. named "upnp_diagnostic_log.txt"

Previous 2.81 version is still working like before.

Thanks for reporting this. A new version will be released very soon and will have this fixed.

This seems to be fixed with 2.83.1, Thank you!