So to fix this issue check if you have any antiviruses blocking BO3 especially in the firewall and see if your game version is outdated. If that doesnt work go to Steam --> Settings --> Download --> Clear Download Cache relog into steam and restart steam then see if that works. If that also doesnt work there might be another issue and that is the Steam Cloud. Your steam cloud might be also outdated wich prevents your game from updating (i think) So what you want to do is go into: Library --> Black Ops 3 --> Properties --> General and untick the Steam Cloud box then go to Local Files --> Verify Integrity Of Game Files wait until it finishes close Steam FULLY by closing it through task manager (RCTRL SHIFT ESC). And you issue should be fixed hope this helps!!