@evtrompa is it possible you updated streamlit? I just spent all day trying to figure out why my nginx configuration was suddenly causing an endless Please wait… error. It turns out it was because the endpoint /stream was changed to /_stcore/stream in new-ish versions of streamlit, which I found here: Any changes regarding websocket for Streamlit v1.14 vs. 1.18?. I adjusted my configuration and now things seem to be working fine. Sharing in case it helps with your issue and because the documentation about this change still seems sparse.