Google Apps and Android and iOS devices

[Leonard J. Peirce]

Before I try going down the Google Support rabbit hole I figured I
would ask on this list.

We have had Shibboleth working for Google Apps SSO for a while now.
My question is:  has anyone who has setup Shibboleth for Google Apps
been able to add an account for their managed domain on an Android
or iOS device?

When I try it on Android 7 I enter my email address and after being
informed that the account is managed by our domain I accept the terms
and privacy policy.  I then get a message saying that it couldn't sign
in and there was a problem contacting our IdP (even though it did know
the FQDN of our IdP).  From sniffing packets we don't see anything
coming even near our IdP when we test this.

On iOS the behaviour is different.  When adding an account I am
directed to our IdP and after authenticating I am sent back to the
same screen to add an account.

Any insights would be greatly appreciated.

- Leonard