Common Issues

Connection issues

Gemini Enterprise can't authenticate against the MCP server

Authentication failures usually mean the OAuth values in the GCP data store form don't match what Coupler.io issued. Check the following:

• Confirm the Client ID and Client Secret in the GCP form match the OAuth app in the Coupler.io destination step.
• Verify the Authorization URL, Token URL, and MCP Server URL were copied exactly, with no trailing spaces.
• Make sure the Scopes field is set to mcp.

If you regenerated the client secret in Coupler.io, you must paste the new secret into the GCP data store form — the old one no longer works.

I lost the client secret

The client secret is shown only once, at creation. If you didn't copy it, open the Gemini Enterprise destination step in Coupler.io and click Regenerate secret to issue a new one, then paste it into the GCP data store form.

Regenerating the secret keeps existing access tokens valid, but any place already using the old secret to request new tokens will need the new value.

I can't create or manage the OAuth credentials

Only an account admin or owner can create, regenerate, or delete the OAuth app used for Gemini Enterprise. If the buttons are disabled, ask an admin or owner on your Coupler.io account to set up the credentials.

Data issues

Gemini Enterprise sees fewer rows than the Coupler.io preview shows

A mismatch between the Preview in Coupler.io and the data Gemini Enterprise receives can occur when the same identifier appears multiple times and deduplication affects the export differently than the preview.

Don't rely on the Preview tab alone to confirm what Gemini Enterprise will receive. Always verify the actual row count after running the flow. You can also configure a Google Sheets export to cross-check the number of rows and see what's missing.

If specific rows are missing, note the relevant IDs and contact Coupler.io support with the data flow details — this type of discrepancy requires engineering investigation.

Permission errors

"You've reached your destination limit" or AI usage is restricted

Coupler.io plans have limits on destination type. If you're using Gemini Enterprise as a destination and also sending data elsewhere (for example, Google Sheets), you may hit this limit.

To resolve this, either:

• Remove the other destination and use only Gemini Enterprise, or
• Upgrade to a higher Coupler.io plan that supports multiple destination types.

Each active data flow counts toward your plan limits. If you created a test flow with a different destination, delete it to free up your destination slot or upgrade to a higher plan.