<![CDATA[401 Response: Invalid application Id on call to Registrations API]]>I'm able to create a user and receive back the user info including the FusionAuth assigned user Id, but when trying to register that same user to an application I continue to receive a 401 Status Code:

  • Code: [Invalid]registration.applicationId.
  • Message: An application with Id [my app id] does not exist.

Additionally, I have multi-tenants set up on FusionAuth Cloud deployment.

Also, I am currently using FusionAuthSyncClient from the FusionAuth.Client NuGet package.

Any help would be appreciated.

Thank you.

]]>https://fusionauth.io/community/forum/topic/925/401-response-invalid-application-id-on-call-to-registrations-apiRSS for NodeSun, 14 Jun 2026 19:24:40 GMTWed, 07 Apr 2021 00:43:05 GMT60<![CDATA[Reply to 401 Response: Invalid application Id on call to Registrations API on Tue, 13 Apr 2021 17:12:05 GMT]]>Referencing/linking below for future guidance for folks who view this post:

https://fusionauth.io/community/forum/topic/900/authentication-for-an-application-with-web-client-and-mobile-front-ends

]]>https://fusionauth.io/community/forum/post/2800https://fusionauth.io/community/forum/post/2800Tue, 13 Apr 2021 17:12:05 GMT<![CDATA[Reply to 401 Response: Invalid application Id on call to Registrations API on Sat, 10 Apr 2021 01:45:06 GMT]]>@joshua

Everything works great when I have an application assigned in each tenant. Before proceeding to make an application per tenant, I just wanted to make certain that applications can't be shared across tenants. The good thing is that your APIs make it easy to create them.

Thanks for your support!

]]>https://fusionauth.io/community/forum/post/2779https://fusionauth.io/community/forum/post/2779Sat, 10 Apr 2021 01:45:06 GMT<![CDATA[Reply to 401 Response: Invalid application Id on call to Registrations API on Fri, 09 Apr 2021 22:56:38 GMT]]>Hi @mehamm!

All applications are associated with one and only one tenant.

You may find some answers to your questions around multi-tenancy here:

https://fusionauth.io/blog/2018/09/24/multi-tenancy-in-a-single-tenant-architecture

I will also excerpt from the article

A FusionAuth tenant is simply a namespace where Applications, Groups, and Users exist

Another article that might be of interest is below:
https://fusionauth.io/blog/2020/06/30/private-labeling-with-multi-tenant

These articles should help you understand the concept of tenants as it applies to FusionAuth.

I hope this helps!

Thanks,
Josh

]]>https://fusionauth.io/community/forum/post/2778https://fusionauth.io/community/forum/post/2778Fri, 09 Apr 2021 22:56:38 GMT<![CDATA[Reply to 401 Response: Invalid application Id on call to Registrations API on Thu, 08 Apr 2021 20:30:14 GMT]]>This error happens when trying to register a user to an application that doesn't reside within the user's tenant, which leads me to my next question:

Can you have one application that is shared across tenants?

The FusionAuth documents covering multi-tenants gave me the impression that you could, but it seems as though you have to have an app residing within the same tenant you wish to register a user to that is also a member of that specific tenant.

I'm looking for insight as to how multi-tenants works within FusionAuth. At this point, it looks like you have to have a copy of an application within every tenant, even though it is essentially the same application - roles, etc.

Thank you.

]]>https://fusionauth.io/community/forum/post/2770https://fusionauth.io/community/forum/post/2770Thu, 08 Apr 2021 20:30:14 GMT<![CDATA[Reply to 401 Response: Invalid application Id on call to Registrations API on Wed, 07 Apr 2021 21:19:22 GMT]]>This is actually a 400 Response.

The fusionauth-app.log shows the following error:

The error may exist in io/fusionauth/api/domain/UserMapper.xml

The error may involve defaultParameterMap

The error occurred while setting parameters

SQL: INSERT INTO user_registrations (id, applications_id, authentication_token, clean_speak_id, data, insert_instant, last_login_instant, last_update_instant, timezone, username, username_status, users_id, verified) VALUES (?, ?, ?, ?, ?, ?, ?,?, ?, ?, ?, ?, ?)

Cause: org.postgresql.util.PSQLException: ERROR: null value in column "users_id" violates not-null constraint

]]>https://fusionauth.io/community/forum/post/2760https://fusionauth.io/community/forum/post/2760Wed, 07 Apr 2021 21:19:22 GMT