3CX v20 Cloud & Twilio E.164 Formatting - No Outbound Calls

[Eastcott]

Issue:

• Outbound calls from 3CX v20 Cloud to Twilio are failing with error 32101: The called number is not correctly formatted.
• Twilio requires all called numbers to be in E.164 format (e.g., +13052225000).
• Even when dialing with the + and configuring outbound rules to prepend +, Twilio receives the number without the plus sign (e.g.,13052225000).

Troubleshooting Steps Taken:

• Outbound rules have been set to prepend + and country code.
• Attempted dialing with explicit E.164 format from endpoints.
• Verified all available number formatting options in the 3CX v20 Cloud interface.
• Confirmed that the “Outbound Parameters” tab and SIP header manipulation are not available in 3CX v20 Cloud.

Findings:

• 3CX v20 Cloud does not expose SIP header or outbound parameter controls to end users.
• Number formatting is handled internally by 3CX, and the platform appears to strip or ignore the + before sending to Twilio.
• There is no way for the user to force E.164 formatting with a plus sign from the current web interface.

Next Steps Requested:

• Need 3CX support to advise on how to ensure outbound numbers are sent to Twilio in E.164 format (with the +).
• If this is a platform limitation to allow E.164 formatting for SIP trunks?