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.