When pushing your code, "main" is the branch name you're pushing to. Check if that's the branch on your github.
If that doesn't work, you can start from scratch and remove all git instances by running
rm -rf .git
Then start the process all over again and set your branch name to "main" then run "git push origin main"
Possible errors:
1. Origin - you maybe be pushing to the wrong origin.
git set-url origin git@github.com:username/test.git
2. Branch - you may be on the wrong branch. switch to the right branch and then push
git checkout branch
3. Add & Commit - remove to use these commands before pushing
git add .
git commit -m "commit message"