Can't Get a client_id/secret to work

I’ve tried any combination of:

and none will successfully complete the oauth flow with authorizing my application, etc.

Please advise.

Hi,

while using https://trello.com/app-key, have you specified the allowed origins?

You should specify the origins (e.g. https://example.com) that your application is allowed to redirect back to following the authorization flow. Trello will prevent a redirect to any origin not specified here.