POST /api/v2/conversations/calls returning 400 malformed participant address

NICE CXone API & Integrations
1

Trying to initiate an outbound call via the REST API. Getting a 400 Bad Request with the message “malformed participant address”.

The JSON payload looks standard:

{
 "to": { "phoneNumber": "+13125550199" },
 "from": { "phoneNumber": "+18005550100" }
}

Checked the formatting. No spaces. The E.164 prefix is there. scripts work fine with these numbers. Is the API expecting a specific URI scheme like tel:+1… instead of just the string? Tried that too. Still fails.

2

The to object usually needs a name field, not just phoneNumber. Try adding that. Also, make sure your from number is actually a provisioned outbound caller ID in Genesys Cloud. The API validates that the originator exists and is permitted to call that destination. Check your telephony settings.

3

adding the name field didn’t fix it. turns out the issue was the from number. it wasn’t fully provisioned in the telephony settings for outbound use. once i added it to the allowed caller IDs, the 400 vanished.