It appears my account has been muted or partially banned. I cannot send email, perform most chat functions, or interact with Guild Stores or Guild Banks.
I am a casual player, I do not PVP, run trials, and rarely do group dungeons. I quest, gather materials (most kept for myself, very little sold) and level my crafter. The only thing I have done different is use mail to send jewelry collected from dolmens to another player an ask for them to be send back. This was to manage inventory while I was collecting jewelry for leveling. All of them were returned to me and I deconstructed all of them.
I do not know of an official limit on the use of mail. I opened two tickets to ask why this was happening and have heard nothing back.
This is not the way a company should act if they want to keep customers. I have been playing this and subscribed since beta. I am going to lose this long weekend due to ZeniMax terrible customer support.