How to fix "Use Browser Cache" from Google PageSpeed?

Question

Google

I've been struggling with this issue for several days. Server on digital ocean - ubuntu 14, site on wordpress. I tried all the instructions I found on the net, including the answer of Ocean himself - https://www.digitalocean.com/community/questions/l...
Nothing helps, as he wrote this error - he writes. All methods that I tried were based on edits in .htaccess. Maybe I don't know something? It was possible to do it on a regular hosting, but not on DO.