Firefox Community Forum

I edit a newsletter substack and sometimes I have links embedded in it. Mozilla denies me access to those links when I check the newsletter. Do I have to cancell Mozilla protection to have full access to the links in my newsletter from substack?

Hi everyone,

I'm having trouble accessing my local network devices (a 3D printer and Raspberry Pi) using short hostnames like "http://impressora3d" or "http://impressora3d/". Firefox keeps blocking the connection with the "Looks like there’s a problem with this site" error page.

I've captured a network log using 'about:networking' and I can see that: 1. DNS resolution works perfectly and points to my local IP:

  "CompleteLookup: impressora3d has 192.168.1.10"

2. Firefox is upgrading the request to HTTPS (port 443) automatically:

  "nsSocketTransport::ResolveHost [...] impressora3d:443" -> "pushing io layer [0:ssl]"

3. The device rejects it because it only listens on HTTP (port 80):

  "Bad Socket 804b000d" (NS_ERROR_CONNECTION_REFUSED)

What I have already tried: - Disabled "HTTPS-Only Mode" entirely in settings. - Checked "Secure DNS" (DoH) settings (set to Increased Protection and added exceptions). - Cleared history and used "Forget about this site" on the hostname. - Typed "http://" explicitly.

Firefox still refuses to connect via plain HTTP (port 80). Is there any hidden 'about:config' preference or HSTS cache forcing this behavior for local unformatted domains?

Thank you!