If another person has pushed to the same branch as you, Git won't be able to push your changes:
git push origin main To https://HOSTNAME/USERNAME/REPOSITORY.git ! [rejected] main -> main (non-fast-forward) error: failed to push some refs to 'https://HOSTNAME/USERNAME/REPOSITORY.git' To prevent you from losing history, non-fast-forward updates were rejected Merge the remote changes (e.g. 'git pull') before pushing again. See the 'Note about fast-forwards' section of 'git push --help' for details.
You can fix this by fetching and merging the changes made on the remote branch with the changes that you have made locally:
git fetch origin Fetches updates made to an online repository git merge origin YOUR_BRANCH_NAME Merges updates made online with your local work
Or, you can simply use
git pull to perform both commands at once:
git pull origin YOUR_BRANCH_NAME Grabs online updates and merges them with your local work