Nice! There's no chance for confusion now.
This is a different issue from the one sterretje mentioned where the files at the absolute #include path are not compiled. With that issue, you do not get a "No such file or directory" error for the #included file.
It looks like there is an alternative syntax like //server20.local/videos/Blink_Blink/Blank/Home_Can_Address.h, so you can give that a try.
But I think the best approach would be to mount the share. That will get you to the point of being able to #include header files. You would still need to put the files in a standard library installation if you want source files to be compiled.
You must use the "" syntax if the file is not in a standard library installation.