Search does not work trying to add a member to a B2C Enterprise app.

Hello Ryan Wilson,

Welcome to Microsoft Q&A Platform. Thank you for reaching out & hope you are doing well.

I will try to clarify your doubts regarding this issue.

The search function in the Enterprise Applications > Users and groups > Add user/group blade is constrained by the underlying Microsoft Graph API query used by the Azure portal:

Hard Limit: The portal often limits the initial API call to retrieve a fixed number of user objects, typically 100, without providing an obvious way to paginate or scroll through all results.

B2C Context: In Microsoft Entra External ID (B2C), the directory can contain a large number of consumer users. This large dataset makes it very easy for a broad search to return over 100 matches, "burying" the specific user you are looking for outside the visible set.

This behavior is by design to prevent excessively long queries in the portal UI, but it creates a user experience issue when searching a large directory.

Would suggest you to check and let us know below points as:

Can you successfully find and select the user when you search for their full, complete User Principal Name (UPN) or email address (e.g., ******@domain.com)?

Approximately how many total users are currently in your tenant? (Confirming a large directory size supports the 100-limit theory).

Till then will suggest below workaround like:

The solution is to use methods that avoid the portal's search limitation or bypass the portal entirely.

1. Try to Search by Unique Identifier

Use the user's full and unique identifier instead of a partial name. A unique search term is highly likely to return only one result, bypassing the 100-item limit. Type the exact, complete UPN or email address (e.g., ******@contoso.com) into the search box.

2. Use Microsoft Graph API or PowerShell

For bulk assignment or when the UI fails, use programmatic tools as this is the official solution for managing assignments at scale.

Use the Microsoft Graph API's POST /servicePrincipals/{id}/appRoleAssignments endpoint or the Microsoft Graph PowerShell module's New-MgServicePrincipalAppRoleAssignment cmdlet to assign the user object ID to the application's service principal ID.

Do refer: https://learn.microsoft.com/en-us/entra/identity/enterprise-apps/assign-user-or-group-access-portal?pivots=portal

https://learn.microsoft.com/en-us/graph/api/serviceprincipal-post-approleassignments?view=graph-rest-1.0&tabs=http

3. General Troubleshooting (If the issue persists)

If the unique identifier fix doesn't work, perform these basic steps:

Verify User Status: Go to Microsoft Entra ID > Users and confirm the user's account is present and Block sign in is set to No.

Clear Browser Cache: Clear your browser cache or use an InPrivate/Incognito window to eliminate any stale session data.

Hope this helps! If it answered your question, please consider clicking Accept Answer and Upvote. This will help us and others in the community as well.

If you need more info, feel free to ask in the comments. Happy to help!

Regards,

Monalisha