GPT store disappeared last weekend has never come back

Last Wednesday I discovered that the store was open on my gpt. So I turned one of my gtp’s live. Then, I went to look at a couple of other gpt’s and on the last one that I looked at, when I hit the back button some kind of message flash across the screen that said something about server error. Then the standard interface popped up. I have not seen the store since then. Has anyone else experienced this. And if so, what was the remedy.