Git push to Heroku never pass from Writing and Total objects message's step

I'm a web development student. In the course, they teach using a free Heroku account.

Turns out I can't push to Heroku anymore. When I try, I stop at the beginning, at the step shown below:

sssv-721 git:(master) git push heroku master -v
  Pushing to https://git.heroku.com/sssv-721.git
  Enumerating objects: 188, done.
  Counting objects: 100% (187/187), done.
  Delta compression using up to 4 threads
  Compressing objects: 100% (57/57), done.
  Writing objects: 100% (154/154), 2.10 MiB | 102.40 MiB/s, done.
  Total 154 (delta 95), reused 151 (delta 94)
  POST git-receive-pack (2202066 bytes)

It just doesn't get past that step.

There are no pending commits. I've already restarted the computer. I've already deleted the project folder and made a git clone of the app straight from Heroku. I've already tried doing a git push from different branches. Nothing did work.

The strange thing is that push to github works perfectly.

I'm using Ubuntu v20.04.3 LTS, Rails v6.0.4.1, Git v2.25.1 and Heroku CLI v7.59.1.

I appreciate any help.