When launching the web client, we're getting the error
You are not allowed to used Microsoft Dynamics GP
Please sign out and sign in with an authorized account.
We've found two causes for this error. One is covered by Mariano here:
https://community.dynamics.com/gp/b/gpmarianogomez/archive/2015/03/12/you-receive-quot-you-are-not-allowed-to-use-microsoft-dynamics-gp-please-sign-out-and-sign-in-with-an-authorized-account-quot-when-accessing-web-client-with-directory-account
and the second is below.