I'm trying to set up OpenId Connect to connect to ADFS, and received an error: MSIS9267: No Client credentials found in the request. Client '<guid>' is configured as a confidential client

Does anybody have any suggestions on where to look for a solution? 

I'm also having difficulty making changes on the plugin side as I can't authenticate.  I can disable the plugin, but then I can't configure it.  As soon as I do, it tries to authenticate me and borks - effectively kicking me out.  Any suggestions on how to tweak settings without the GUI?

TIA