Task: Send an SMS message with Plivo

n8n workflow:
{"name":"","nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[250,300],"parameters":{},"typeVersion":1},{"name":"Plivo","type":"n8n-nodes-base.plivo","position":[500,300],"parameters":{"to":"+14156667778","from":"+14156667777","message":"Hello world!"},"credentials":{"plivoApi":""},"typeVersion":1}],"active":false,"settings":{},"connections":{"On clicking 'execute'":{"main":[[{"node":"Plivo","type":"main","index":0}]]}}}