Weird URL problem implementing OAuth with Google

Hi. I just tried implementing OAuth using Google for FM16. When I set up my OAuth client ID on Google I stupidly put HTTPS instead of HTTP in the URL of our Filemaker server. So when I clicked on sign in with Google from FM I get an error 400 from Google.

So I went back to my Google Console and fixed the URL. Everything saved fine. But still when I click on sign in with Google from FM it tries to use the incorrect address with HTTPS. It's like it is cached in a preference somewhere and I don't know how to get rid of it. So far I have:

• Restarted FMS
• Restarted the server
• Turned off Google under client authentication, restarted the server and started again.
• Tried a fresh install of FM Client on a different computer.
• Completely deleted my credentials in Google and started with a fresh client ID and done all the above again.

Still it tries to use the wrong URL for my server. Although the URL has updated with my new client ID from Google.

I have ran out of ideas. Any help appreciated.