Github unable to merge unrelated histories in this repository code example

Example 1: fatal: refusing to merge unrelated histories

git pull origin master --allow-unrelated-histories

Example 2: fatal: refusing to merge unrelated histories

git pull origin master --allow-unrelated-histories
git pull <remote> <branch> --allow-unrelated-histories

Example 3: refusing to merge unrelated histories

git pull origin branchname --allow-unrelated-histories

Example 4: fatal: refusing to merge unrelated histories

fatal: refusing to merge unrelated histories