title: Why "git push" is rejected? ("git pull" doesn't help)
body: <p>My current branch is <code>my_branch</code>. Trying to push the changes to the remote repo I get:</p>
  
  <pre><code>$ git push
  Counting objects: 544, done.
  Delta compression using up to 4 threads.
  Compressing objects: 100% (465/465), done.
  Writing objects: 100% (533/533), 2.04 MiB | 1.16 MiB/s, done.
  Total 533 (delta 407), reused 0 (delta 0)
  To git@......git
     4ed90a6..52673f3  my_branch -&gt; my_branch
   ! [rejected]        master -&gt; master (non-fast-forward)
  error: failed to push some refs to 'git@......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.
  </code></pre>
  
  <p>Trying to <code>git pull</code> results in:</p>
  
  <pre><code>$ git pull
  Already up-to-date.
  </code></pre>
  
  <p>Why I get this error?
  How could I resolve this problem and perform <code>git push</code> successfully?</p>