21707: Short Code SID is required to associate to a Messaging Service.ERROR: 21707error-21707 page anchorERROR Error - 21707error---21707 page anchor Short Code SID is required to associate to a Messaging Service.short-code-sid-is-required-to-associate-to-a-messaging-service page anchorYou attempted to add a short code to your Service, but you forgot to include the SID of the short code you would like to add.