my project is not saving and i don't know why

The project.json is most likely exceeding 5 MB.
Download the project, then enable “show file extensions” (windows):
Now rename the “.sb3” part to “.zip”, go in, and find “project.json”, and look at the size. Or other reasons such as an asset exceeding 10 megabytes, you can read the other limits here

noisey-time wrote:

my project is not saving and i don't know why

Well i fixed it now it's just the music file i used

noisey-time wrote:

(#3)

noisey-time wrote:

my project is not saving and i don't know why

Well i fixed it now it's just the music file i used

You'll have to cut it into peices then, as said by #2 it's just that music exceeding the file limit, so you'll require to cut it into for example 2 parts or more if that doesn't province.