--- "@context": https://schema.org "@type": TechArticle "@id": https://www.twilio.com/docs/api/errors/13000#article headline: "13000: Conference Noun cannot be mixed with Number nouns" url: https://www.twilio.com/docs/api/errors/13000 inLanguage: en dateModified: 2026-06-09T11:00:42.000Z author: "@type": Organization name: Twilio Developer Education Team publisher: "@type": Organization name: Twilio --- # 13000: Conference Noun cannot be mixed with Number nouns Log Level: WARNING ## Description This warning occurs when your `` verb uses a `` noun together with `` nouns, or when `` is used more than once inside the same ``. Use `` to connect the current call to a named conference room. Use one or more `` nouns when you want `` to call phone numbers. ### Possible causes * Your TwiML nests both `` and `` inside the same `` verb. * Your TwiML includes more than one `` noun inside a single `` verb. * Your application generates `` dynamically and appends conference and number nouns to the same response. * You used a simultaneous dialing pattern for `` nouns when you intended to place the caller into a conference. ### Possible solutions * Update your TwiML so each `` uses only one approach. Use a single `` noun to join a conference room, or use one or more `` nouns to dial phone numbers. * Remove any extra `` noun so the `` verb contains only one conference target. * If you want to ring several phone numbers and connect the first answer, remove `` and use multiple `` nouns inside ``. * If you want multiple participants in the same conversation, route each participant to the same named `` instead of mixing `` with `` nouns in one ``. * Inspect the final TwiML your application returns and confirm that each `` contains only the noun type required for that call flow. #### Additional resources * [TwiML Voice: ``](/docs/voice/twiml/dial) * [TwiML Voice: ``](/docs/voice/twiml/conference) * [TwiML Voice: ``](/docs/voice/twiml/number)