13258: Dial->Sim not supported in this realm

This error occurs when Twilio receives a <Sim> noun inside a <Dial> verb in a realm that does not support that behavior. Twilio's current <Dial> documentation lists the supported nouns for <Dial>, and Twilio's regional availability guidance explains that features unavailable in a target Region will not work in that Region.

• Your TwiML response includes <Sim> nested inside <Dial>.
• The call is being executed in a Twilio realm or Region where <Dial><Sim> is not supported.
• The application was moved to, tested in, or routed through a different Region without verifying Voice feature availability for that Region.

• Update the call flow to use a currently documented <Dial> noun that matches your use case, such as <Number>, <Client>, <Conference>, <Sip>, <Application>, <WhatsApp>, or <Queue>.
• Verify which Twilio realm or Region is handling the call and confirm that the required Voice feature is supported there before returning the TwiML.
• If you need to keep using <Dial><Sim>, move that workflow to a realm that supports it; otherwise redesign the flow around supported Programmable Voice nouns in the target Region.

• TwiML Voice: <Dial>
• Regional product availability
• Understanding Twilio Regions