Question: When using Atlassian's Sourcetree I try and and "Refresh OAuth Token" and I see this error:

```
This site can’t provide a secure connection
localhost sent an invalid response.
Try running Windows Network Diagnostics.
ERR_SSL_PROTOCOL_ERROR

```

Answer: 
The issue here is we were developing a website that sets the HSTS header such that all localhost requests now require HTTPS.

The work-around is to remove localhost from your domain security policies.  

If Chrome is your browser, you can do that here: chrome://net-internals/#hsts  

Under the heading **Delete domain security policies** enter `localhost` in the 'domain' input and press `delete`

Now try and "Refresh OAuth Token" again.
Using Chrome I had this issue, my workaround for this was:

1. Open an incognito Window
2. Paste in the localhost address and change HTTPS to HTTP
3. Refresh page and I'm authenticated

I'm on SourceTree version 3.3.8