Microsoft Entra External ID - Customers - how to trigger sign-up flow from link

Question

Microsoft Entra External ID - Customers - how to trigger sign-up flow from link

Kevin 10

Hi - I'm using External ID in an external tenant (customer) and wanting to provider a "sign up" link in an email. Ideally that would also prepopulates the users email address.

I've trying setting the "prompt=signup" in the oauth authorize request but get this error "AADSTS90023: Unsupported 'prompt' value.".

How can I achieve this using Entra External ID for customers?

Thanks

Raja Pothuraju 24,385 Reputation points Microsoft External Staff Moderator

2024-08-27T13:23:26.7066667+00:00

Hello @Kevin,

Thank you for posting your query on Microsoft Q&A.

I understand that you're using an External ID tenant and have been providing a sign-up link via email, hoping to prepopulate the user's email address during sign-up. You attempted to use the prompt=signup parameter in the URL, which resulted in an error stating "Unsupported 'prompt' value."

The prompt=signup parameter is not supported. Instead of using prompt=signup, try adding the login_hint or prompt=select_account parameter in your sign-up URL.

Please test this approach and let me know how it works.

Thanks,
Raja Pothuraju.
Raja Pothuraju 24,385 Reputation points Microsoft External Staff Moderator

2024-08-30T20:19:26.1266667+00:00

@Kevin,

Following up to see if the below suggestion was helpful. And, if you have any further query do let us know.
Bambam Deo Kumar 0 Reputation points

2025-07-05T13:17:32.5666667+00:00

Hi, prompt=select_account didn't work in my case, it still showing login screen, while I want to prepopulate email on signup in readonly mode.