It sounds like maybe your printer is trying to force to you connect using HTTPS, but it doesn't actually have an SSL certificate on it. Try manually typing in http://192.168.1.5 to force Firefox to connect via HTTP instead.

Hope this helps.

That did help, but it took two tries. The browser automatically inserts (or changes) the prefix of the URL to "https://" and blocks it, but I can edit the address bar to change it back to "http://" and allow access.

Same thing with the router's web page, which also has an internally defined name "http://routerlogin.net" and opens up with one pass through the security (after entering a username and password on a popup window). The home page also switches to "https" when navigating to an individual page. In this case, the security warning also pops up, but allows an override.

I can see the logic, in that the browser's protection addon doesn't know the difference between public and local network address (although if it begins with 192. that's a clue!), and a public web page could use "http" instead of "https." And (maybe) it learns after the first override for each page address. I do know it takes longer to populate when the security is bypassed.

The printer control page "http://192.168.1.132" has been "learned." The router must be accessed through "http://routerlogin.net." But they both work now. Thanks for that suggestion!

My older Samsung printer also runs a web server at its LAN address for administering it.

I've always been able to login from other computers on my local network to check toner, see page counts, and so on.

There is no "force Firefox [v. 82] to connect via HTTP" in my case.

Every single attempt to access http://192.168.0.100 is rewritten by the browser to https://192.168.0.100 which I gather requires a certificate to be presented--which the old printer does not offer--after which Firefox declares "Try again."

FF Fanboy from day 1.

Not happy with current behavior. Would love a way out of this hole.

Thank you.