Call fails when using GHL automation

Mar 28 • Issues

🚨 GHL Workflow → Synthflow Caller Error: “Marketplace Action Error 500”

Hey everyone, I’m having an issue integrating Synthflow with my GoHighLevel workflow.

🔧 What I’m doing:

I’ve created a workflow in GHL where the Synthflow AI Caller is supposed to call a lead once they submit a form.

📍 Setup:

• I’ve added the Synthflow Marketplace action properly.

• I’m using the Model API Key, not the App Key.

• The model is active and works perfectly inside the Synthflow app.

• The model is set to outbound and has a US number.

• The fields are correctly mapped and passed (Name, Phone Number).

• I’ve tested US numbers and they DO get called directly from Synthflow.

❌ The issue:

Every time the workflow runs in GHL, I get this error:

Marketplace Action Error - Request failed with status code 500

✅ What I’ve already tried:

• Regenerating the model + API key

• Testing with different models

• Testing different contacts/numbers

• Verified everything is properly connected and credentials match

• Ensured it’s NOT a Norwegian number (U.S. numbers only)

• Model and phone number are active and valid

Anyone else had this problem and found a solution? Could really use the help — been stuck on this for days.

Thanks in advance 🙏

4 comments

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