Have been using EE for about a year now, with nice speeds 
However, for a few months I have some errors:
1) I used to be able to login using the /wp-admin/ URL. However, this now gives a 502 bad gateway error. I have to login into /my-account/ on the front-end, then I can go to wp-admin
2) When clicking Purge cache (using the NGINX helper plugin) gives an error 500. Purging seems to work just fine, when I change something I can see the change on the site no problem.
Anyone knows how to solve this?