The "Missing cookie" error (also shown as "A session cookie is required with this Phantom") means your Phantom doesn't have a session cookie saved, so it has no way to connect to your LinkedIn, Instagram, or other platform account. To fix it: open your Phantom's setup, find the account connection step (usually the first or second step), connect your account, then save and relaunch. If you're triggering the Phantom via API or an integration like Zapier or n8n, include the sessionCookie key and value in your API argument.
If your cookie is expired or invalid rather than missing, see How to Fix "Expired" or "Invalid" Session Cookie Errors instead.
Why you're seeing this
Your automation may show one of these messages:
- "Missing cookie"
- "A session cookie is required with this Phantom"
This error means your Phantom doesn't have a session cookie saved, so it has no way to connect to your LinkedIn, Instagram, or other platform account. Without it, the Phantom can't run.
This is one of the first things to set up when using PhantomBuster, and it's straightforward to fix.
How to fix it
If you set up the Phantom in the Dashboard
The most common cause is that the connection step was skipped or left empty during setup.
- Go to your PhantomBuster Dashboard and open the Phantom showing the error.
- Go to the Phantom's setup and find the step where you connect your account.
→ This is usually the first or second step and asks you to connect LinkedIn, Instagram, or another platform. - Make sure an account is selected. If the field is empty, connect your account now.
- Save your setup and relaunch the Phantom.
If you're not sure how to connect your account, see:
- Automate faster with the PhantomBuster Browser Extension (recommended method)
- How to Connect LinkedIn Accounts to PhantomBuster
- How to Connect and Manage Non-LinkedIn Social Media Accounts
If you're launching via API or integration (Zapier, n8n)
When you trigger a Phantom via API or through an integration such as Zapier or n8n, the session cookie needs to be passed directly in your argument.
Make sure your API argument includes both the sessionCookie key and its value.
For full guidance on updating a session cookie via API, see How to Update a Phantom's Session Cookie via API.
Frequently asked questions
What does the "Missing cookie" error mean?
Your Phantom doesn't have a session cookie saved in its setup, so it can't connect to your LinkedIn, Instagram, or other platform account.
How is this different from an "Expired" or "Invalid" session cookie error?
"Missing cookie" means no cookie was ever saved, typically because the connection step was skipped during setup. "Expired" or "Invalid" means a cookie was saved but is no longer valid. See How to Fix "Expired" or "Invalid" Session Cookie Errors.
Why do I need a session cookie at all?
PhantomBuster uses a session cookie to stay connected to your platform account without requiring your password. Without it, the Phantom has no way to authenticate.
What's the easiest way to add a session cookie?
Use the PhantomBuster browser extension, it captures and updates your cookie automatically while you're logged into the platform.
How do I pass a session cookie via API?
Include both the sessionCookie key and its value in your API argument. See How to Update a Phantom's Session Cookie via API.
If the error keeps showing up
If you've added your session cookie and still see the error, get in touch with our Customer Care Team.
If possible, include:
- The name of the Phantom where you saw the error.
- A screenshot of your connection step in the Phantom setup.
- The exact error message from your logs.