What happens when a Toll-Free message is identified as spam?

Toll-Free Number (TFN) messages identified as SPAM will be rejected and error code 255 returned. Sinch continuously monitors for senders with a high number of SPAM rejections. If the SPAM message content is not resolved, the TFN is subject to blocking and deprovisioning. 

Please see our developer docs for more information on error codes. 

Learn more about Toll-Free Numbers from Sinch.