This happend to me when pushing bigger changes to my git server. The usual size is 2MB,
so what I did is just set the limit to 2MB and it ran through fine:

git config --global http.postBuffer 2M

Here some addtional technical information:

     http.postBuffer
           Maximum size in bytes of the buffer used by smart HTTP transports
           when POSTing data to the remote system. For requests larger than
           this buffer size, HTTP/1.1 and Transfer-Encoding: chunked is used
           to avoid creating a massive pack file locally. Default is 1 MiB,
           which is sufficient for most requests.