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Facebook Conversions API Not Working: Token, Errors and Retries

Last checked against Meta's documentation. By Muhammed Abdul Kalam. Data loss

Quick fix

Facebook conversions api not working usually comes down to the access token or the request. Make sure the token is generated for the right pixel by someone with developer privileges, and still valid. Then check for 4xx responses, which mean the payload is invalid, and retry non-client errors such as timeouts with a 1500 millisecond timeout.

  • Check you have developer privileges to see Generate access token.
  • Check the token belongs to the right pixel or system user.
  • Check responses: 2xx is valid, 4xx is invalid.
  • Retry timeouts and send events promptly.

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What this error means

The Conversions API sends events from your server to Meta, and every call needs a valid access token. If the token is missing, expired or lacks access, or the payload is malformed, events are rejected or dropped, and Meta only returns minimal error detail.

Why it happens

2Token expired or invalidated

Token lifetimes vary and may end early.

How to tell if this is you: Calls that worked now fail.

3System user lacks access

A system user token is rejected if the user lacks access to the resource.

How to tell if this is you: The pixel is not assigned to the system user.

4Invalid payload

A 4xx response means the payload is invalid, with little detail.

How to tell if this is you: Responses return 4xx.

5Timeouts and network errors

Network errors may drop events unless you retry.

How to tell if this is you: Requests time out.

How to fix it

Generate a fresh token

For: You can't generate a token, Token expired or invalidated, System user lacks access

  1. Ask someone with developer privileges to open the pixel Settings and use Generate access token.
  2. With your own app, assign the pixel to the system user and generate the token.

Fix the requests

For: Invalid payload, Timeouts and network errors

  1. Treat 4xx responses as invalid payloads and fix the event data.
  2. Retry non-client errors such as timeouts, using a 1500 millisecond timeout.
  3. Send events in real time or close to it.

How long it takes

Meta says most requests respond in under 600 milliseconds, and recommends a 1500 millisecond timeout. Short-lived tokens last about 1 to 2 hours and long-lived tokens about 60 days, but these can change.

How to stop it happening again

  • Don't rely on a fixed token lifetime.
  • Use a system user token for automated server sending.
  • Log response codes so 4xx errors do not go unnoticed.

From my desk

The access token is the usual weak point. Someone generated it under a personal login, the person left, and nobody noticed until events stopped. After that I check the response codes the server gets back, then whether failed requests are retried. I also confirm the pixel and server events share an event ID.

Muhammed Abdul Kalam

When to get help

  • You've worked through the checks and the numbers or status still aren't right.
  • The setup involves a tag manager, Shopify app or developer you cannot reach and nobody can explain it.
  • Results are suffering during a launch or sale and every day costs real money.

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FAQs

Why can I not see Generate access token?

The link is only visible to users with developer privileges for the business.

Does my app need App Review?

No. The app does not need App Review, and you do not need to request permissions.

How long does a token last?

Short-lived tokens last about 1 to 2 hours and long-lived tokens about 60 days, but that can change without warning.

What do 2xx and 4xx responses mean?

A valid payload returns 2xx, and an invalid one returns 4xx with minimal error detail.

Should I retry failed requests?

Yes, when the response indicates a non-client error such as a timeout.

Related fixes

Sources

Meta