There are a lot of cases where you can't watch it, not because you can't watch it, but because you've already downloaded it and can watch it
You can watch it if you change the suffix of the file you downloaded
For example, if the suffix is oldfriends01.rm.bt, you can remove the bt and it becomes oldfriends01.rm
An example: if the suffix is oldfriends01.rm.bt, you can remove the bt and it becomes oldfriends01.rm.bt. Old Friends 01.rm
All in all, the last part of the filename should be the format of the movie, and then you don't need to put anything after the name of the format of the movie.