I'm working out a user self-provisioning workflow that I'd like to expose to the guest user. The form validates the uniqueness of their chosen user ID. The script calls IDVault.get as part of the validation process. it works fine with a logged in user, but fails with this error, Script error in idvault.get(): You need to login to execute service vdm, it is marked as requiring authentication, when executed as the guest user.

I've set up User App to use a real user as the guest user, not [Public]. Is there a knob I can turn somewhere to make this work?