Tmux not sourcing my .tmux.conf

It's most likely that you haven't started a new tmux server process. You say that you've closed your ssh session and started a new one, but that wouldn't have any effect on the tmux server; one of the main benefits to using tmux is that sessions can survive that type of activity.

Try running tmux ls to check if the server is still running. If it isn't it should complain about that.

If you instead get a list of sessions, attach to each of those in turn and close them. The tmux server process will die when the last session is closed. Then the next time that you start a new session a new server process will be created and it will read the tmux.conf file.

If you don't want to close the existing sessions you can ask the tmux server to read the configuration file with tmux source ~/.tmux.conf.

Use tmux kill-server, after that start a new tmux session.

This can also be done from within tmux, by pressing Ctrl+B (prefix key) and then : to bring up a command prompt, and typing:

:source-file ~/.tmux.conf

Read http://blog.sanctum.geek.nz/reloading-tmux-config/