I have seen several posts in StackOverflow related to this issue, but yet I cannot find a solution:

Example of posts:

• What does “Git push non-fast-forward updates were rejected” mean?
• git pull says up-to-date but git push rejects non-fast forward
• Never-ending GIT story – what am I doing wrong here?

I’m working with gitlab, in a branch where I’m the only user, and every single time I try to commit/push a change using Eclipse, I get the same error:

Things I have checked before trying to commit/push:

• “git pull” returns: Already up to date.
• “git status” returns: On branch main Your branch is up to date with 'origin/main'. nothing to commit, working tree clean
• “gitk –all” returns (here you can see the monster tree this issue is creating):

Every merge shown in the tree contains:

This is my config:

[core]
    repositoryformatversion = 0
    filemode = false
    bare = false
    logallrefupdates = true
    ignorecase = true
[remote "origin"]
    url = XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    fetch = +refs/heads/*:refs/remotes/origin/*
    puttykeyfile = XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    push = HEAD:refs/heads/main
[branch "main"]
    remote = origin
    merge = refs/heads/main
    rebase = false
[gui]
    wmstate = zoomed
    geometry = 893x435+104+104 227 196

I have been using git with a project I own in github without issues for years, but since I have started to use gitlab at work I have the exact same issue with every single project we have, and we cannot find a solution to this (we have been using SVN for years so we are beginners in the GIT/gitlab world).