> For the complete documentation index, see [llms.txt](https://docs.coupler.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.coupler.io/sources/category/email/convertkit/common-issues.md).
# Common Issues
## Connection issues
My API key is rejected when setting up the data flow
Make sure you're using the correct key. In Kit, go to **Settings → Advanced → API** and copy the **API Secret** — not the shorter public API key. The API Secret is the one Coupler.io needs for data access. Paste it carefully with no leading or trailing spaces.
The data flow connects but returns no data
Check your **start date** setting. If it's set to a future date or a very recent date with no activity, the response will be empty. Use the date picker to set a start date that covers a period where you know data exists — for example, your account creation date or a few months back.
## Missing data
Some subscribers are missing from the export
Kit's API returns subscribers based on their status and the start date you've set. Unconfirmed or cancelled subscribers may not appear depending on your account settings. Also check that your start date isn't too recent — subscribers created before that date won't be included.
Purchase records aren't showing up
Purchases are only available if you use Kit Commerce or have integrated a third-party purchase tracking tool that writes back to Kit. If you don't have purchase data in your Kit account, the Purchases entity will return empty results.
Custom field values aren't appearing in the Custom fields entity
The **Custom fields** entity only returns field definitions (the key names and labels you've created), not subscriber-level values. To see actual custom field data for each subscriber, use the **Subscribers** entity — custom field values are nested inside the `fields` column there.
## Permission errors
I get an "unauthorized" or 401 error
This usually means the API key has been regenerated or revoked. Go to **Settings → Advanced → API** in Kit and check whether the key matches what you entered in Coupler.io. If Kit generated a new key, update it in your data flow's source settings.
## Data discrepancies
Subscriber count in Coupler.io doesn't match what I see in Kit
Kit's dashboard counts may include subscribers in all states (active, unconfirmed, cancelled), while the API may filter by state depending on how the request is structured. If your numbers differ significantly, check the `state` field in your exported data and apply a filter for `active` status to match the dashboard view.
Broadcast data doesn't include open rates or click rates
Kit's API does not expose per-broadcast engagement metrics like open rates or click-through rates. These are only available inside the Kit dashboard. The Broadcasts entity covers metadata (subject, send date, content) but not performance stats.
## Rate limits
The data flow fails intermittently with timeout or rate limit errors
Kit's API has rate limits that apply to high-volume accounts with large subscriber lists. If you have tens of thousands of subscribers, the sync may take longer or occasionally hit limits. Try setting a more recent start date to reduce the volume of data being pulled in a single run, or split entities across separate data flows.
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