# Resource Catalog exceptions

> Common Resource Catalog Service exceptions encountered during startup, including Ledger subscriber errors caused by SQL Server unavailability.

## 500.30 ASP.NET Core app failed to start - UiPath.ResourceCatalogService.Web.Api.Ledger.LedgerServiceException: Ledger subscriber ResxSubscriber could not be started

### Exception

```
Exception Info: UiPath.ResourceCatalogService.Web.Api.Ledger.LedgerServiceException: Ledger subscriber ResxSubscriber could not be started.
```

This exception is typically preceded in the Application event log by a Microsoft.Data.SqlClient.SqlException (error 40) and a "SQL Server is shutting down" entry.

:::tip
Check the Application event log for a SQL connection error immediately before the Ledger subscriber exception to confirm the cause.
:::

### Cause

SQL Server was not available when Resource Catalog attempted to start the `ResxSubscriber` Ledger subscriber. This happens when SQL Server runs on the same machine as Orchestrator and has not finished starting when Orchestrator starts after an OS restart.

### Solution

1. Confirm that SQL Server is running and accepting connections.
2. Stop the Orchestrator site in IIS Manager.
3. Start the Orchestrator site in IIS Manager.