Looking for advice on resolving a 400 error when initiating outbound calls.
Context:
The API rejects my request with "message":"Malformed participant address". I am using a standard E.164 format for the to parameter.
{
"to": { "phoneNumber": { "phoneNumber": "+12125550199" } },
"from": { "phoneNumber": { "phoneNumber": "+18005550100" } },
"wrapUpCode": "none"
}
Question:
Does the Genesys Cloud REST API require specific formatting for the phoneNumber object, or is this a permission issue disguised as a validation error?
You need to ensure the from address matches an outbound call routing destination configured in Genesys Cloud. The API validates the from number against your organization’s allowed destinations. If it doesn’t match, you get a 400 error. Check your routing settings.
TL;DR: Check your outbound call routing.
If I remember correctly, the from number must be explicitly whitelisted in your outbound call routing destinations, otherwise the API rejects it as malformed regardless of E.164 formatting. You can verify this via GET /api/v2/outbound/callingskills to ensure your number is mapped correctly.
The issue is likely not just the routing destination but the specific structure of the from object when using the REST API directly versus the SDK. While the previous answers correctly identify the outbound routing requirement, the 400 “Malformed participant address” often stems from the from object missing the explicit id or name field if you are trying to map it to a specific destination ID, or simply failing validation if the number isn’t active. However, a more robust check involves verifying the destination status via the API before making the call.
Verify your outbound destinations are active and correctly mapped using the following Python snippet. This ensures the number exists in Genesys Cloud before you attempt the call, preventing the 400 error.
from genesyscloud import api_client, outbound_api, conversations_api
def validate_outbound_number(phone_number, client):
api_instance = outbound_api.OutboundApi(client)
try:
# Search for the destination by phone number
dests = api_instance.get_outbound_campaigns_destinations(
expand="phoneNumbers"
)
for dest in dests.destinations:
for ph in dest.phone_numbers:
if ph.phone_number == phone_number:
return dest.id, dest.status
return None, "Not Found"
except Exception as e:
return None, str(e)
# Usage
dest_id, status = validate_outbound_number("+18005550100", platform_client)
if status != "ACTIVE":
print(f"Destination {dest_id} is {status}. Fix routing first.")
- Ensure the
from number is listed in GET /api/v2/outbound/campaigns/destinations.
- Check that the destination status is
ACTIVE.
- If using the SDK, pass the
destination_id in the call request instead of just the phone number for higher reliability.
- Verify OAuth scopes include
calls:write.
The simplest way to resolve this is to verify the outbound call routing configuration using the API directly. The previous suggestions about whitelisting are correct, but you need to confirm the specific destination ID. Use this curl command to list your destinations:
curl -X GET "https://api.mypurecloud.com/api/v2/outbound/callingskills" \
-H "Authorization: Bearer $TOKEN"
Check the fromAddresses array in the response. The phoneNumber in your POST body must match one of these exactly. If it does not exist, you must create it via POST /api/v2/outbound/callingskills.
In my Azure Function consumers, I often see this error when the managed identity has read access to routing but the number itself is missing from the destination list. The API returns 400 because it cannot validate the E.164 string against a known, approved resource. Ensure the number is added to the destination before retrying the call initiation. This prevents the “malformed” error which is actually a validation failure, not a format error.