@drealhelen while ur pulling together the workflow info tamy asked for, this exact error from the Send a text message node almost always traces to a few Twilio-side things worth checking first.
most common one if ur on a Twilio trial account — u can only send SMS to phone numbers that are explicitly verified in ur Twilio console. go to Twilio Console → Phone Numbers → Verified Caller IDs and confirm the destination number is in that list. paid accounts dont have this restriction but trial does.
right after that is geographic permissions, which catches a lot of people because nobody mentions it in docs. Twilio defaults to ONLY allowing SMS to the country of ur Twilio account. if ur sending to a different country, go to Console → Messaging → Settings → Geo Permissions and enable the destination country explicitly.
the from-number itself can also cause it — needs to be a Twilio-purchased number with SMS capabilities enabled (not voice-only). check at Console → Phone Numbers → Active Numbers, click the number, and make sure the SMS capability checkbox is on.
last common one is the credential setup in n8n. for Twilio u use Account SID + Auth Token from the MAIN account dashboard. if u created a subaccount and grabbed those credentials with the wrong scope, ull get Forbidden even tho the creds look valid because subaccount credentials behave differently from primary.
if all of those check out and u still get the error, post the workflow json + the exact From number ur using (mask the last 4 digits) and we can go deeper. one last gotcha for US destinations specifically — A2P 10DLC registration is now required and unregistered numbers get Forbidden too. longer fix but worth ruling out.