The environment is my home network and also opening ports on the router for outside access. This is not a permanent situation. I am just interested in doing this. On a VM, I have a backend listening on 8055 and a front-end on port 3000. Both are http. Accessing this on a browser elsewhere on the network works but completing fields on a form causes the browser to show warnings. But it works. So I thought let's move to Https. For the front end, I set the web server to use Https with a self signed certificate. There are the expected "are you sure" messages in the browser but so far so good. So Https ....:3000 works. For the backend, I used caddy and reverse proxy Https:8555 to http:8055, with a TLS internal. Again, accessing the backend on a browser elsewhere works once the certificate is accepted. But, the front-end can not fetch data from the backend. The browser console is showing CORS errors. I have set CORS origin in the backend. And it works for http. So my question is will Firefox not fetch data when that backend is using a self signed certificate?