Project saved in "Multiple files based on markers" doesn't work

Hi everyone,
I would need help with creating a video using Camtasia 9.

I'm working on creating a video composed of three different parts. I wish that each part could be assigned a percentage of completion.
I would also like that if the user came out of the video and came back later, the video started from the point where it was interrupted.
I inserted a marker for each part and produced the video by selecting the option "Multiple files based on markers".
Once the process is completed, trying to open the file locally: "XXX_player.html" I get the following error: "Sorry, we are unable to connect to this content. Please try refreshing the page or click here for more help ".
Trying to open the .m3u file directly gives me the following error: "Windows Media Player encountered a problem while downloading the playlist".

Unfortunately I can not get the whole thing running.
Has anyone ever encountered and solved a similar problem and could you give me some advice?

Thank you very much for your help.
M.