ERR_TASK_HISTORY on Zapier: Task history not updating. Root cause: Task history cache not refreshing or database sync issue Step 1: Distinguish between a display bug and a genuine sync failure. Zapier's Task History page (zapier.com/app/history) can sometimes show stale data due to browser caching, not an actual problem with your Zaps. Before investigating further, do a hard refresh: press Ctrl+Shift+R on Windows/Linux or Cmd+Shift+R on Mac. Wait 30 seconds and reload the page. If the task count updates, this was a display issue only. If the history genuinely shows no new tasks despite your Zap being turned on and trigger events occurring, proceed to the next steps. Step 2: Verify the Zap is turned on and the trigger is receiving data. Go to zapier.com/app/zaps and confirm the toggle next to your Zap is green (On). A grey toggle means the Zap is paused and will not run. Next, click the Zap name → click the trigger step → click "Test trigger". Zapier will attempt to fetch a recent trigger event from the connected app. If it returns "We couldn't find any [records]", the trigger app is not sending data — the issue is upstream in the connected app, not in Zapier itself. Step 3: Check whether tasks are being consumed by a different Zap. If you have multiple Zaps connected to the same trigger app, it is possible that a different Zap is processing the events before this one. Go to zapier.com/app/history and use the "Filter by Zap" dropdown to isolate history for your specific Zap. Also check whether you have a "Catch Hook" Zap that might be consuming webhook events before they reach the intended Zap. Zapier delivers each webhook event to only one Zap. Step 4: Review the Zap's error log for silent failures. In the Zap editor, click the action step that should be creating task history entries. Click "Zap History" in the left sidebar. Filter by "Errors" using the status dropdown. Zapier sometimes logs a task as an error rather than a success, which means it appears in the error log but not in the main task count. Common causes include the action app returning a non-200 HTTP response, a required field being empty, or the connected account having expired credentials. Step 5: Reconnect the trigger app account if credentials have expired. Go to zapier.com/app/connections and find the connected account for your trigger app. If it shows a yellow warning icon or "Reconnect" button, the OAuth token has expired. Click "Reconnect" and complete the OAuth flow for the trigger app. After reconnecting, go back to your Zap, click the trigger step, and run a test to confirm data is flowing again. Many task history gaps are caused by quietly expired OAuth tokens that Zapier does not prominently flag. Step 6: Contact Zapier support with your Zap ID if the issue persists. If task history is still not updating after the above steps, the issue may be on Zapier's infrastructure side. Go to zapier.com/app/zaps, click your Zap name, and copy the Zap ID from the URL (it looks like a long number). Contact Zapier support at zapier.com/help with the Zap ID, the approximate time the history stopped updating, and the name of the trigger app. Zapier's support team can check server-side logs that are not visible to users.