If your on console make sure your wired connection not wireless, i had that problem but it wouldn't even load the main menus cause apparently the serveres need more internet connection than what my Xbox could get wirelessly
I think there is nothing you can do for it expect hope blizzard gets their shit together.
Why i blame blizzard? Season 6 i didnt hear any of my friends or me lose connection to server but oh boy the last few weeks...(at least once they admited they have problems)
I think it's just the servers because as far as I can remember when I bought the game it worked fine and for past 3-4 months it's not working fine, I get 90-100 RTT sometimes I kill someone and on my screen there is no hit registration effect or the sound!