Self deployed on a VPS behind an NGINX reverse proxy ... Backend dropouts

[paraplegic]

I'm using rootless podman container(s) to run a Reflex app on a cloud VPS behind a native NGINX reverse proxy. The problem I'm getting is that some browsers have a back-end timeout, while Firefox does not (at least not on all platforms). Chromium is consistently unable to connect to the back end. I've searched extensively for solutions, and tried a lot, but thus far, I'm coming up blank. I am thinking about switching out NGINX, but that seems extreme.

nginx.txt

Podman pod is working great, and the Front end is using CADDY to serve the static site (3001) and the Back end is using reflex run in PROD mode (8001) to run on the localhost ports. AFAICT I have done everything correctly, but as the results are PARTIAL success (FIrefox is OK, Chrome/Chromium is not). Also tried unsuccessfully Thorium, Brave etc on Ubuntu, and Chromium/Firefox on FreeBSD. Clearly, I am missing something. Has anyone seen this problem before?

[paraplegic]

I am investigating switching from NGINX to Caddy. :-/ Would prefer an NGINX solution. Anyone?

[paraplegic]

The Chromium console is showing this error:

Mixed Content: The page at 'https://aquaterrapm.ca/' was loaded over HTTPS, but attempted to connect to the insecure WebSocket endpoint 'ws://aquaterrapm.ca/_event/?token=087e610b-20f0-451a-941c-1f76f684eff9&EIO=4&transport=websocket'. This request has been blocked; this endpoint must be available over WSS.