Im just getting back on the server after about a year. When i try to send anything to chat it says "Cannot send chat message."
First of all, Welcome back! If you need any help, feel free to ask or check the wiki (I suggest reading the new player guide to get you up to date). Like weeh has said, try /c t to reset town chat as if you were previously a supporter then your supporter chat obviously wouldn't work if you are now just regular member. That's my best guess. (Couldn't of been muted, that wasn't around then.)
When you enter the waste, if no one is near you (local) it should say that no one is close enough to hear you EDIT - just sent you a PM to see if that works for you
hit escape, options, multiplayer settings, chat settings. Make sure the Chat Settings says Shown. if you have it on Commands Only or Hidden, your chat will not work.