Hi @Kyle1983b14_ESO. Just few things to check that you might already have done (sorry if so) - just check that the guild has not slipped below 50 (that prevents the guild from having an active guild store) Also make sure that the correct guild is listed - do know that the default guild it opens for you to use can be different to the one you wanted to interact with. Also have you closed and opened your session as sometimes the UI plays up.

I know that mentioning your server and platform will help people let you know if they experiencing anything on their side. Hope the issue gets solved soon so that you can trade again.