[git] remote: repository not found fatal: not found

I faced exactly the same error message. When I run ls -a, I found out that .git was missing (surely I deleted it by inadvertence in previous days). As what I have locally is the same as on the Github repository, I simply removed my local "folder" and cloned the remote one again. After that, everything worked fine for me:

rm -rf my_project
git clone https://github.com/begueradj/my_project.git