The help information for the "OAuth Domain" setting says:
For the purposes of redirection, subdomains are considered to be under their parent domain. Registering example.com would allow a redirect_uri of foo.example.com for example.
However, subdomains are not being accepted for me. Instead, I get "An error occurred while login into an application." with the description:
unexpected domain on proxy url
In my case, my "OAuth Domain" is set to
mattlunn.me.uk, but I'm trying to use
mattlunn.dev.mattlunn.me.uk. Setting the OAuth Domain to
dev.mattlunn.me.uk doesn't work either.