CodeDeploy will not accept GitHub OAuth when instance is in a different region

I am at my wits end here. I am trying to set up a CodeDeploy deployment with my EC2 instance for GitHub, but whenever I try to verify the token name it either says "There seems to be a problem with your session" or when I clear cookies and try changing the region, it will show the correct window but it doesn't respond after hitting the "Confirm" button. In the URL I can see that the pop up window for the connection is using a "us-west-1" region, but the EC2 and CodeDeploy appication is set up in "us-east-1". When I do clear cookies and it shows the correct window and then I hit the "Commit" button, nothing happens but the console shows this error:

Uncaught DOMException: Permission denied to access property "signalGitHubFinished" on cross-origin object

Which makes me think this is a CORS issue between the regions. I did find a similar issue like this way back in 2015 but it was resolved with someone saying "This issue is fixed now". But it's clearly not fixed for me. PLEASE HELP.