Git clone fail with 502 bad request.

I have Gitlab CE on my 8 GB server, all is working well, out of 10 projects I have one project is not getting cloned. Project size is only 947 MB, where as other projects are 1.2, 1.3 GBs and they get clone easily. It is a wordpress site with 1000s of images and hence the size.

I am not very expert in Linux, but I found that Unicorn is existing because the memory size is above 500MB, apache error shows that git-upload-pack timeout, I try to set proxyTimeout to 600 but no use.

Gitlay only produce info that it is terminated, and error cause is unavailable. I am not sure exactly what is failing and if there is any problem. I try to reconfigure it as well.