Copilot not reliable: chats and prompts disappear automatically

I have so many problems with Microsoft 365 Copilot (Premium). It automatically deletes my chats. Also, the recent prompts in the chats suddenly disappear, and only the older ones are visible. I restart it, but sometimes they appear; mostly, they are lost. I also tried using the web version. It has the same problems. I refresh the page multiple times. The lost chats appear sometimes, but mostly they are lost completely. Pinned chats get automatically unpinned and lost. I can't find them again.