DUPLICATE_CONVERSION
Google Ads rejected your conversion as a duplicate. Learn why duplicates happen — missing order_id, overlapping schedules, repeated records — and how to implement proper deduplication.
Common Causes
| # | Cause | Likelihood | Details |
|---|---|---|---|
| 1 | Missing order_id | Very Common | Without an order_id, Google deduplicates based on GCLID + conversion action + conversion time. If you upload the same record twice (common with retry logic or overlapping time windows), Google treats it as a duplicate. |
| 2 | Overlapping automation schedules | Common | Multiple automation tools or relay schedules uploading the same conversions. For example, running a daily relay and a weekly relay that overlap, or having both TUOCA and a manual CSV upload for the same data. |
| 3 | Timezone causing re-processing | Less Common | If your pipeline processes records based on date ranges and the timezone shifts (e.g., UTC vs. local time), records near the boundary may be processed in two consecutive batches. |
What the duplicate means
Google Ads has already received the event you are uploading. Start with one rejected row: compare its conversion action, original event time, click identifier and order ID against the earlier successful upload. Keep those values stable when retrying.
A duplicate result does not tell you whether every other row succeeded. Check the upload’s individual results before resending a batch.
Fix the repeated event
- Use a stable event ID. An invoice ID or CRM event ID is useful; a customer ID alone is not unique when that customer buys twice. Use the same ID for retries of the same event, and different IDs for genuinely different events.
- Find every sender. Check manual files, scheduled uploads and other automation tools. Give each business event a clearly owned upload path.
- Keep timestamps consistent. Send the original conversion time with its timezone, not the current upload time. Overlapping lookback windows can be intentional for late-arriving data, but need deduplication.
- Check reporting separately. Tracking the same sale in GA4 and an offline action can inflate combined reporting without producing this API error. Review which actions contribute to your campaign goals.
Google’s import guidelines explain that repeated events are deduplicated. Setting Count to Every does not bypass that protection; it is for distinct conversions, such as separate purchases.
If the invoice value changed
Do not invent a new order ID or timestamp to get the corrected amount accepted as another sale. That can double-count the business outcome.
Use a RESTATEMENT through Google’s conversion adjustment process to change a recorded conversion’s value. Identify the original conversion, preferably by its order ID and conversion action, and provide the adjusted value. An ordinary re-upload of the order ID does not update revenue. Check the adjustment requirements before submitting it.
Where TUOCA helps
When daily exports and repeated runs become difficult to manage, TUOCA Automated Relays give the upload workflow a home. TUOCA checks for duplicate records before upload, and execution history lets you review run outcomes.
That does not replace coordinating your other senders: TUOCA cannot prevent a separate manual file or external automation from uploading the same event. It also should not be treated as an automatic conversion-restatement tool.
Start with one conversion action, inspect a dry run on a plan that includes relays, and compare its source records with an earlier upload. Explore Automated Relays to see how you can manage recurring uploads without rebuilding that workflow yourself.
Technical references checked November 9, 2026.