Here is the request body I am using to create the adset

{
    "name": "My Reach Ad Set",
    "optimization_goal": "LEAD_GENERATION",
    "billing_event": "IMPRESSIONS",
    "bid_amount": "20000",
    "daily_budget": "100000",
    "campaign_id": "120211079900420484",
    "targeting": {
        "geo_locations": {
            "countries": [
                "US"
            ]
        },
        "publisher_platforms": [
            "facebook"
        ],
        "facebook_positions": [
            "feed"
        ]
    },
    "promoted_object": {
        "pixel_id": "977936767456228",
        "custom_event_type": "LEAD"
    },
    "status": "PAUSED",
    "access_token": "{{FB_ACCESS_TOKEN}}"
}

When I try creating the adset without the pixel id I get an error saying pixel required.

Here is the campaign request I use to create the campaign for this adset

{
    "name": "App installs campaign",
    "objective": "OUTCOME_LEADS",
    "status": "PAUSED",
    "special_ad_categories": [],
    "access_token": "{{FB_ACCESS_TOKEN}}"
}

Thanks for any help.