Looks like Google is the responsible one, not Firefox. Don't shoot the messenger.

Set up google search console for that domain, then it will tell you why it’s blocked. It might be a false positive you can flag, or it might be that a host or service has been compromised or contains something harmful. Google’s blocklist is quite aggressive and often blocks entire domains if one of their subdomains has a violation.

You can just disable Google Safe Browsing in the settings.

google owns the internet

Are you using a free subdomain?

I got hit by that, basically forced me to make a Google account and add all my sites to it even though I couldn't care less about SEO and indexing. Now it keeps sending me spam emails about "problems" with my websites. No, I'm intentionally not letting you index this.

What seems to be going on is it's flagging random widespread open-source software as impersonation/phishing login page because it's seen it on a bigger site and assumes you're doing some phishing.

Filed an appeal and it thankfully promptly got resolved. Google ain't known to be friendly to developers.

I want to like that feature because I'm sure it's helpful for the less technically savvy. But I hate that Google can just decide my site is unsafe and essentially cut my sites off the Internet for most people. If Google denies your appeal you have basically zero recourse.

I think we need more info here. I'm guessing this is a locally hosted site? How are you exposing it to the web? DDNS? Reverse proxy? Honestly it's hard to diagnose without knowing your IP, which you definitely shouldn't give us.

Edit: you can check your site here, maybe they'll give you details on why it was blacklisted: https://transparencyreport.google.com/safe-browsing/search

Happend to me recently, with no option to "ignore and continue". I opened the page in private mode and it worked. Weird.

If you have a dynamic IP from your ISP, could be you got unlucky and were given a address previously used by attackers.

Or if you have a static IP on a VPS or similar, they may have had a lot of attacks from the IP Range.

By attacks in this instance I mean people setting up phishing or similar websites as the most common example. A simple web form, probably with obfuscated code. They then send a bunch of emails line "click here to view your invoice"and gather office 365 credentials.

While it's not good that this kind of false positive happens from time to time, I am more thankful this kind of service exists. Yes, there's privacy and security implications, but smart screen has stopped legitimate attacks at our clients before, and we force it enabled wherever possible.

I think people are missing the point here if they say "just click through". Mozilla's reliance on Google could potentially be anticompetitive in nature if Google is essentially worsening a self hosted service which would compete with their own offerings.

Click “ignore the risk” and it will continue to the page. You better be certain you aren’t being man in the middle attacked though.

That's weird. Google is using Safe Browsing to censor the Internet.

You can go to about:config and set browser.safebrowsing.blockedURIs.enabled to false.

It will be better if Mozilla make their own version of Google Safe Browsing. Because less Google is good.