we are running vbulletin forum. As, we were having pretty high loads we were recommended to use Nginx.

After, we migrated to Nginx we are getting 502 and 504 errors constantly like while merging more than 80 posts/threads. Members were reporting this problem when they were searching on forums as well.

I would like some help on how to overcome this problem. I am a noob, so kindly explain the procedure in detail

Thanks