With Brevo already connected, the detail's **Status** tab includes a **Test connection** button that checks, on the spot, that the saved key is still valid against Brevo's real API. **Requirements:** Admin role. 1. Open Brevo's **Details** and go to the **Status** tab. 2. Click **Test connection**. **Result:** "Connection successful" if the key is still valid, or "Couldn't connect: [reason]" if the key was revoked or changed (section 8). Remember that "Connection successful" checks the key, not email sending — if sending fails, check the verified sender or authenticated domain in your Brevo account (section 3). The example below again uses Google Sheets — with Brevo connected, the same "Status" tab shows the "Test connection" and "Disconnect" buttons.