Getting ACS20016 error while user should have access

Hello,

I have configured 2 AAD tenants.

Tenant A has a multi-tenant web application (with custom domain).

Tenant B has successfully subscribed on this application using the consent Grant Access page.

I can see the application on Tenant B as read-only mode (with application Sign-ins graph).

When I login using a user of tenant A, I get a successful redirect.

When I login using a user of tenant B, I get the "ACS20016: The account is not configured to sign-in to this company." error.

Are there other steps involved to grant access to the users of tenant B?

I've read http://social.msdn.microsoft.com/Forums/windowsazure/en-US/dab7743a-0274-4dc2-9130-df5910f97b0f/acs20016-the-account-is-not-configured-to-signin-to-this-company?forum=WindowsAzureAD but that doesn't help me.

If you could check any tracing, that will be helpfull:

Kind regards,

Jonas