I'm MentalEdge, a.k.a. EdgeMentality.
In addition to now modding this community, I have long hosted the MENTAL northstar servers.
The state of Titanfall
Both Titanfall games are technically playable using their vanilla versions. You may need to manually select a different datacenter to connect to at the main screen, if the one your game defaults to in your region has too few players, or other issues.
However, DDOS attacks may at times put one or both games out of comission completely. If you are on console, you are out of luck, and will simply have to wait to play another time. This issue has seemingly let up, and become far less common of an occurrance than it once was.
Northstar Client
If you are on PC, and wish to play titanfall 2, there is the option of using the Northstar client. I highly recommend this, as it fixes security vulnerabilites that are still present in the vanilla version of the game, to this day.
Northstar adds an old-school style server browser, which will let you connect to community run servers (some by yours truly), running various game-modes and mods, improving the game in some aspects beyond what vanilla could do. There are even entirely new game-modes!
You can find more information on the Nortstars homepage.
New to the game
If you are new to Titanfall, I host the only beginner servers currently on northstar, they will let you get the hang of the game without constant bullying from veteran players speeding around the map at mach 3. The servers are kept free of stompers by an automated kicking system that detects high skill players.
You might also be interested in watching The The ULTIMATE Movement Guide for Titanfall 2
Vanilla does still work from time to time, which is good for those of you on console. Though you may have to hop datacenters to get into a game, at times.