Using IdentityModel.OidcClient with Dropbox

Example:

My registered redirect URI at google is https://127.0.0.1. If I now send an authentication request with the redirect URI set to https://127.0.0.1:51931. Google accepts this redirect URI, because the port doesn't change the destination.

Dropbox on the other hand seems to be very strict when it comes to the redirect URIs. The redirect URI from the authentication request has to match exactly the registered redirect URI (port included).

I would prefer to use random ports to avoid problems on machines where ports might be not available do to e.g. firewall settings. This way it's possible to switch from a blocked port to a free port without having to register another redirect URI.