Safari only wants to connect to localhost via HTTPS

Do a lot of local development and recently I've noticed that I cannot connect to non-HTTPS services running on localhost. If the services provide HTTPS then I am able to connect, but every time I try something like "http://devsite:8000", Safari always tries to access "https://devsite.local:8000".

Using Chrome, I can properly access the site.

Perhaps the issue is HSTS?

I am running Safari 10.1 on macOS Sierra.

Solution 1:

Actually, it looks like it was HSTS.

I followed the directions posted here:

1. Close Safari.
2. Delete the ~/Library/Cookies/HSTS.plist file.
3. Reopen Safari.

And now localhost sites are working correctly.