Hi Vidudhala,

Based on what you shared, the issue is very likely not related only to your multi-tenant app.

In your screenshots, the tenants for Users, UsersLibrary, and UsersServices are marked as inactive (Is_Active = false). These are core system eSpaces used by the platform for authentication and internal services. If their tenants are inactive, the runtime can’t initialize properly, which typically results in 503 – Application Backend Unavailable errors.

That would explain why even basic endpoints are failing.

How you recover depends on the environment:

• OutSystems Cloud / Personal / Trial
  • You won’t have direct database access. In this case, you’ll need to contact OutSystems Support to re-enable those tenants.
• Self-managed (on-prem or private cloud)
  • Reactivate the affected tenants in the system table, then republish Users, UsersLibrary, and UsersServices, and restart the OutSystems services to ensure a clean startup.

As a general rule, system eSpaces should never be altered at tenant level, especially in multi-tenant scenarios, as they are required for the platform to function correctly.

Best, Miguel

Understood. That’s exactly what I’m asking — could you please advise on how to re-enable it and set it back to true? I mean how to contact " OutSystems Support to re-enable those tenants. "

Hi Vidudhala,

If this is an OutSystems Cloud / Personal / Trial environment, you can’t re-enable those tenants yourself.

To proceed, you need to open a support request with OutSystems:

1. Go to Customer Portal
2. Open a Support Case
3. Describe the issue clearly, for example:
   1. Environment name
   2. That the tenants for Users, UsersLibrary, and UsersServices were set to inactive by mistake
   3. That the environment is now returning 503 – Application Backend Unavailable
   4. Request them to reactivate those system tenants

Unfortunately, there’s no supported way to fix this from Service Studio or Service Center in cloud environments.

Best, Miguel