I think this will happen if the endpoint URLs in /o/.well-known/openid-configuration are HTTP instead of HTTPS.
If you change Debug messages to DEVELOPER and Display debug messages is Yes then this error becomes a bit more helpful, you'd probably get: error/invalidpersistenterror (url: For security reasons only https connections are allowed, sorry.).
However I don't think you should need to change the debug settings to see this and there's actually a bug with the language strings, see MDL-71860.