15004: Action Callback URL must be absolute when updating in-progress calls

When you update an in-progress call with the twiml parameter, use an absolute URL for any action callback. This requirement applies to <Gather>, <Record>, and <Pay> when you create or update a call with inline TwiML.

• You updated a live call with inline twiml and used a relative action URL such as /process_gather.php. <Gather> and <Record> can use relative URLs in other contexts, but when you start or update a call with the twiml parameter, the action URL must be absolute.
• The TwiML sent in the twiml parameter includes <Gather>, <Record>, or <Pay> with an action that depends on the current document URL instead of a fully qualified callback URL. Twilio uses the twiml parameter directly instead of fetching TwiML from a url.
• Your <Pay> verb uses an action URL that is not absolute or does not use https. <Pay> only accepts https for the action URL.

• Replace each relative action value with a fully qualified URL that includes the scheme and hostname, such as https://example.com/voice/process-gather.
• Review the TwiML you send in the twiml parameter and update every <Gather>, <Record>, and <Pay> action to an absolute URL before you resend the call update.
• If you use <Pay>, set the action to an absolute https URL.

• Update a Call
• TwiML <Gather>
• TwiML <Record>