Hey there,
I'm sorry that you are having this problem. First, I would check that you are playing on 1.11.2
If you are using the right version, and Meepcraft is the only server you have problems connecting, then it is most likely due to the blacklist. Meepcraft is currently bypassing the EULA Blacklist (since it is hard to fund the server), and that causes a small portion of players to have troubles connecting. One thing you can do is download the SquidHQ launcher (free) which bypasses the blacklist.
If you are still having problems, let us know and we are here to help:)