You can no longer use some domains like .dev locally because its owner (Google) has added this domain to the HSTS preload list and a secure connection is automatically enforced. The ".dev" domain landed on the HSTS preload list in Firefox 59.0b7 and this means that Firefox will automatically try a secure connection to these TLDs.

I'm struggling to get Firefox to use `http` instead of `https` when I'm doing development on my laptop. Playing with the `HTTPS-only` in the settings didn't make difference. With enable or not. I tried to add my `localhost` to exception list, but Firefox still tries to use `https.` I understand the security concern from Firefox team, but if I'm trying to load by typing `http,` I would appreciate if Firefox gave me a benefit of doubt that I know what I'm doing. Maybe I could disable this feature temporarily. Why force `https` on `localhost`? Please allow us some flexibility.

I think it was my mistake. I didn't see that inside the php code there was a line forcing the use of `https.` Once I tried to create a simple `hello world.html,` the site worked.

Thank you all for the reply, and sorry for the noise.

Best Regards

mg.