This happened to me after I worked on a site that used https and then tried switching back to one that does not.
Unfortunately, the accepted answer did not work for me. What I needed to do was:
- Open the Firefox History (ctrl+h)
- Find the page (
127.0.0.1:3000
, in my case) - Right-click it and choose the last option: “Forget About This Site”
If you use localhost
– with our without port – to access your page, then you will notice that localhost
does not show up in your history. This makes it impossible to access the “Forget About This Site” option.
Fear not! You can work around that issue.
- Visit your site using
127.0.0.1
instead oflocalhost
. So, for example,localhost:3000
becomes127.0.0.1:3000
. - Now open the Firefox History (ctrl+h)
- Find the page (
127.0.0.1
), right-click, and “Forget About This Site” - Now, access
localhost
and you will find that it works again. This is because forgetting about127.0.0.1
cleared data for both127.0.0.1
as well as forlocalhost
.