HTTP 502 and infinite loading when accessing tunneled website

I have followed the documentation over on: Create a remotely-managed tunnel (dashboard) · Cloudflare Zero Trust docs , and created a tunnel from http://localhost:8080 to a subdomain on one of the domains I have on Cloudflare.
I am running cloudflared and the localhost webapp on the same machine, running Linux Mint, and using the 64-bit Debian cloudflared package.
The tunnel’s status is “healthy”, the tunnel dashboard automatically created the appropriate DNS record, and the service is pointed at http://localhost:8080. I can access localhost:8080 in my browser and I am presented with my application.
When I try to access via the “public hostname” of the tunnel, I get a HTTP 502 if I try using http://, and if I try using https://, then I get “The connection has timed out.”

As it turns out, this only occurs on the machine that is hosting the webserver. Other people have been able to access the link just fine, and I can access it on other devices. On the machine running cloudflared, I get the above issue when trying to access my domain.
Is there any way to fix this happening to my own machine? Or is that a restriction of how the tunnels work? I have used similar services in the past (serveo, etc) and have not had an issue like this before.