Need Help: “Invalid OAuth 2.0 Access Token” When Calling Facebook Graph API in Pabbly

[sonuku]

Hi Team,


I’m trying to create a workflow in Pabbly Connect that interacts with my Facebook Page using the Facebook Graph API.
I’ve already added the Page to Business Manager, created a System User, assigned my App to the System User, and generated a System User Access Token with all the required page permissions.


However, whenever I make a GET request to the Facebook Graph API using “API by Pabbly,” I receive the error:



Invalid OAuth 2.0 Access Token


The token is newly generated and has full permissions, so I’m not sure why it’s failing.
I need guidance on why this token isn’t being accepted and what configuration might be missing or incorrect.


Thanks in advance for your help.

Pabbly

connect.pabbly.com

 

[Preeti Paryani]

Hello @sonuku,

Thank you for reaching out.

To assist you accurately, we request you to please share the API documentation you are referring to along with the exact endpoint you are trying to use. Additionally, it would be helpful if you could provide a short screencast showing:

• The method you used to generate the System User Access Token
• The permissions added
• The steps followed to retrieve the token

This will allow us to review the configuration and identify what may be causing the “Invalid OAuth 2.0 Access Token” error.

In the meantime, we also recommend using the Custom API Request option available under the respective Facebook application in Pabbly Connect

 

[sonuku]

I am using the official Facebook Graph API documentation for Page endpoints:


Base docs:

Graph API | Developer Documentation

The Graph API allows you to read and write data to and from the Facebook social graph.

developers.facebook.com

Page Posts:



GET /{page_id}/posts


Post Likes:



GET /{post_id}/likes


Send Page Invite:



POST /{page_id}/invited_users

---

2. API Endpoints I am calling in Pabbly Connect​

To fetch Page Posts:



https://graph.facebook.com/v19.0/{page_id}/posts?fields=id,message,created_time,permalink_url&limit=20&access_token={token}


To fetch Likes on a Post:



https://graph.facebook.com/v19.0/{post_id}/likes?limit=500&access_token={token}


To send an invite to a user:



https://graph.facebook.com/v19.0/{page_id}/invited_users


Method: POST
Payload: Form Data (user_id + access_token)

---

3. Method used to generate the System User Access Token​

• Inside Facebook Business Settings
• Created a System User
• Added my Page under Assigned Assets with full permissions
• Added my custom Business App under Installed Apps
• Clicked Generate Token inside System User
• Selected my App
• Selected expiration
• Enabled the required permissions:

pages_manage_engagement
pages_read_engagement
pages_read_user_content
pages_manage_metadata
pages_show_list


Token generated successfully.

---

4. Issue​

When I call the GET request inside Pabbly Connect, I get:



Invalid OAuth 2.0 Access Token


This happens even though:

• The token is newly generated
• The System User, App, and Page are properly connected
• The same token works when tested outside Pabbly (using browser or third-party API tester)

---

I have already shared with the workflow link also.​

 

[ArshilAhmad]

You won't be able to execute endpoints with OAuth 2.0 authentication using the API (Pabbly) module reliably. To do this, you will need to create a custom application.

Application Integration Guide for Developers 🧑‍💻

This article explains the process of integrating your apps in Pabbly Connect.

forum.pabbly.com

For any assistance on how to create a custom application, you can get in touch with our integrations team at the following email address: [email protected]

 

[healthysimplyrecipes]

It definitely sounds like you’ve set everything up correctly on the Business Manager side, so the “Invalid OAuth 2.0 Access Token” error is usually a sign that one small configuration in Meta’s system isn’t matching what the Graph API expects. A few things you may want to double-check:
System User Tokens must be generated from the App’s Business Settings, not from the Meta Graph API Explorer. Tokens created in the Explorer look similar but will always throw OAuth errors when used with a system user.
Make sure your App is in Live mode. System user tokens don’t work properly when the app is still in Development mode the API treats the token as invalid for assets outside dev scope.
Confirm that the system user has both:
– Access to the Page under Business Settings → Accounts → Pages
– Permissions assigned to the system user under the App → Assign Assets → App → Full Control
If you generated a long-lived token using the Business Apps API, verify that the token type is SYSTEM_USER. Any PAGE_ACCESS_TOKEN or USER_TOKEN won’t authenticate correctly in Pabbly API calls.
Finally, make sure the API endpoint you’re calling matches the token type.
System user tokens should authenticate calls like:
https://graph.facebook.com/v20.0/{page_id}?fields=name&access_token=SYSTEM_USER_TOKEN
…and not the /me endpoint (which requires a user token).
If all of those line up, your token should authenticate normally in Pabbly Connect.
Hope this helps this one usually comes down to a small configuration mismatch, but once it’s fixed, everything runs smoothly!