You get this try running pull first to integrate your changes whenever your local branch and your remote branch are not on the same point, before your changes.
remote branch commits : A -> B -> C -> D
local branch commits : A -> B -> C -> Local_Commits
Now clearly, there’s a change D that you don’t have integrated locally. So you need to rebase, then push, which will lead to the following.
remote branch commits : A -> B -> C -> D
local branch commits : A -> B -> C -> D -> Local_Commits
To solve your issue, do the following
git pull --rebase origin branchname
git push origin branchname