Unable to link account

What is it?

This error occurs only during an OAuth flow when attempting to link the provider account to the currently authenticated user. Better Auth blocks the operation if either:

1. The database operation to create/update the linked account fails.
2. The provider is not considered trusted for linking based on your auth configuration (account.accountLinking.trustedProviders).

Common Causes

• The provider is not listed in account.accountLinking.trustedProviders.
• Configuration differs across environments (dev/staging/prod), so the provider appears untrusted in one environment.
• Database write failed due to unique constraint, foreign key violation, or transaction/connection issues.
• A race condition linking the same provider concurrently caused a conflict.
• Pending migrations or a mismatched schema between services caused the write to fail.

How to resolve

Allow linking for the intended provider

• Add the provider id (e.g., github, google) to account.accountLinking.trustedProviders in your auth config.
• Verify you are using the correct provider id/slug that your integration expects.

Fix database reliability and constraints

• Run pending migrations and ensure the schema matches the current Better Auth version.
• Investigate DB errors (deadlocks, timeouts, connection pool limits) and retry if appropriate.

Verify environment configuration

• Ensure the same auth config is deployed to all environments and that environment variables are loaded as expected.
• Double-check that the runtime sees the intended trustedProviders list.