TLS Certificate Recertification After SQL Server Reboots

Issue

After SQL Server reboots, Fivetran may require you to revalidate the TLS certificate for your connection.

Environment

Connector: SQL Server

Resolution

To troubleshoot this issue, do the following:

Set up a self-signed TLS certificate with a long expiration period to reduce the frequency of recertification.
Revalidate the certificate in Fivetran:
i. Go to the affected SQL Server connection page.
ii. Click Test Connection.
iii. Accept the new TLS certificate when prompted.
iv. If the connection still fails, go to Account Settings > General > Validated Certificates & Keys and delete the saved certificate.
v. Repeat the connection test.
Automate TLS certificate validation using the Fivetran REST APIs. After SQL Server reboots, use your automation workflow to trigger the Run Connector Setup Tests endpoint on your chosen schedule.
```
POST https://api.fivetran.com/v1/connectors/{connector_id}/test
```
Set trust_certificates and trust_fingerprints to true to accept the new certificate. For more information, see the Run Connector Setup Tests documentation.

Cause

This issue occurs when a SQL Server reboot resets or replaces TLS certificates, especially if the connection uses a self-signed certificate. When the certificate changes, Fivetran flags the connection and requires recertification before syncs can resume.