Google ads rest api cannot create a campaign "MUTATE_ACTION_NOT_PERMITTED_FOR_CLIENT"

Question

I'm trying to create Google Ads campaigns using the Google Adwords API and getting this error MUTATE_ACTION_NOT_PERMITTED_FOR_CLIENT I'm calling this endpoint: https://googleads.googleapis.com/v10/customers/customerID/campaigns:mutate with the payload:

{
"operations": [
    {
        "create": {
            "status": "PAUSED",
            "advertisingChannelType": "SEARCH",
            "advertisingChannelSubType": "SEARCH_EXPRESS",
            "paymentMode": "CONVERSIONS",
            "name": "TestCampaign",
            "campaignBudget": "customers/${customerID}/campaignBudgets/${budgetId}",
            "biddingStrategyType": "COMMISSION",
        }
    }
]
}

Here is the response:

"errors": [
    {
        "errorCode": {
            "operationAccessDeniedError": "MUTATE_ACTION_NOT_PERMITTED_FOR_CLIENT"
        },
        "message": "A mutate action is not allowed on this resource, from this client.",
        "trigger": {
            "stringValue": ""
        },
        "location": {
            "fieldPathElements": [
{
        "fieldName": "operations",
            "index": 0
        },
        {
            "fieldName": "create"
        },
            {
            "fieldName": "advertising_channel_sub_type"
            }
        ]
    }
},
    {
        "errorCode": {
        "operationAccessDeniedError": "OPERATION_NOT_PERMITTED_FOR_CAMPAIGN_TYPE"
    },
        "message": "This operation is not permitted on this campaign type",
        "trigger": {
            "stringValue": "SEARCH(SEARCH_EXPRESS)"
        },
        "location": {
        "fieldPathElements": [
            {
                "fieldName": "operations",
                "index": 0
            },
            {
                "fieldName": "create"
            },
            {
                "fieldName": "payment_mode"
            }
        ]
    }
}
],