Common Issues

Connection issues

"The API developer key is invalid" error when selecting a spreadsheet

This is a known Google issue that occurs when your browser isn't actively signed in to the Google account you connected to Coupler.io.

Fix: Open a new browser tab and sign in to the correct Google account at accounts.google.com. Then return to Coupler.io and try selecting the spreadsheet again. If the issue persists, try clearing your browser cookies or using an incognito window to re-authorize.

"Access token is invalid" (401 error)

This usually means the OAuth connection between Coupler.io and your Google account has expired or been revoked.

Fix: Go to the Destinations tab in Coupler.io, find your Google Sheets connection, and reconnect it by signing in to Google again. Also check that Coupler.io still has permission in your Google account security settings.

"The service is currently unavailable" error

This means the Google Sheets API is temporarily unavailable — usually due to a brief outage or maintenance.

Fix: Wait a few minutes and retry the data flow manually. If the error continues, check whether the destination spreadsheet opens normally in your browser. If you're running many data flows to the same sheet simultaneously, try staggering their schedules to reduce API load.

Unable to find or select the destination spreadsheet

Coupler.io can only access spreadsheets that belong to or are explicitly shared with the connected Google account.

Fix: Make sure the spreadsheet is owned by — or shared with edit access to — the Google account you connected. Spreadsheets in shared drives may also require additional permissions.

Data issues

Fewer rows than expected appear in the destination sheet

If you defined a cell range (e.g., C1:F50) in Replace mode, Coupler.io will only write data within that range. Rows or columns beyond the range boundaries are silently dropped.

Fix: Either expand your defined range to accommodate all expected data, or remove the range limit and use just a starting cell (e.g., C1) so Coupler.io writes as many rows and columns as the source provides.

Numbers are imported as text or display incorrectly

Coupler.io expects numerical data in standard programming format — plain digits or digits with a dot as the decimal separator (e.g., 2345123.00). If your source uses locale-specific formatting like 2.345.123,00, the import may produce text values instead of numbers.

Fix: Ensure your source data uses dot notation for decimals before it reaches Coupler.io. Coupler.io will then automatically convert the values to match your spreadsheet's locale settings.

Filters, formatting, or formulas are removed after a run

In Replace mode, Coupler.io overwrites the data range it controls. Filters applied to those columns and any formatting in the written cells will not be preserved.

Fix:

• Place formulas in columns to the left of your data start cell — Coupler.io writes rightward from the starting cell and won't touch those columns.

• If you need filters, consider reapplying them via a Google Sheets macro after each run, or use a separate summary sheet that references your data range with IMPORTRANGE.

• For preserving formatting alongside imported data, use the Append mode — existing rows are not modified.

Coupler.io does not currently preserve column filters on re-import. If maintaining filters is critical, use a separate reference sheet for analysis.

"This action would increase the number of cells above the 10,000,000 limit"

Google Sheets caps every spreadsheet at 10 million cells total — across all tabs. This error has nothing to do with how many rows your data flow imports; it's about the total cell count in the file.

Fix: Open the destination spreadsheet and delete unused sheet tabs, empty rows, or empty columns that inflate the cell count. If the spreadsheet is already heavily used, create a fresh spreadsheet as the destination.

This limit is per-spreadsheet and cannot be increased. Repeatedly appending data to a large file will eventually hit this ceiling.

Google API 500 "Internal error encountered"

This error typically points to an overloaded or formula-heavy spreadsheet, a broken formula, or a temporary Google API issue.

Fix:

• Check whether the destination spreadsheet opens and loads quickly in your browser. Slow loading or formula errors are a red flag.

• Clean up the spreadsheet: remove broken formulas, unused sheets, and any cells that reference external data that may be failing.

• If the problem persists, try pointing the data flow to a fresh, empty spreadsheet to confirm the issue is with the file rather than the data flow itself.

Permission errors

Data flow fails because Coupler.io can't write to the sheet

Coupler.io needs Editor access to the destination spreadsheet. Viewer or Commenter access is not sufficient.

Fix: In Google Sheets, open the Share dialog and confirm the connected Google account has Editor permissions. If the sheet is protected (via Data > Protect sheets and ranges), remove or adjust the protection rules to allow Coupler.io to write.

Plan limit reached — can't add a new destination sheet

Coupler.io plans have a limit on the number of destination connections. Hitting this limit blocks new destination setup.

Fix: Review your active data flows and remove any that are no longer needed, or upgrade your Coupler.io plan to increase your limits.