Summary: If an automated or manual SMS message fails to send to a UK guest, it may be because the messaging integration at your property is configured with a US-based sender number. Twilio does not support sending SMS from a US number (+1) to a UK number (+44). This article explains what causes the error and what steps are needed to fix it.
Permissions Required: Brand Admin (to request a change to the messaging integration via your Alliants CSM).
Steps to follow
Check the error message in the conversation or message logs. If it reads "Message cannot be sent with the current combination of To and/or From parameters", this confirms the issue is a mismatch between the sender country and the recipient country.
Check the guest's phone number in their AXP profile. The number should be in E.164 format (e.g.
+447890123456for a UK number). AXP automatically formats numbers to E.164 on import — so if the raw data shows a number without a country code (e.g.07890123456), AXP will have added country code to the profile based on the library.Confirm the sender number configured for your location's messaging integration. If your property is in the UK but the integration is using a US sender number (
+1), SMS to UK guests will fail.To resolve the issue, a Brand Admin at your property must submit a request to configure a UK-based sender number (
+44) in the integration. This must be raised through your Alliants CSM (Customer Success Manager).
Common Questions
Q: Why does the phone number in the guest's Raw Data look different from the number shown in AXP?
A: AXP automatically converts phone numbers to E.164 format when a guest profile is imported. For example, a UK number stored as 07890123456 (without a country code) will be displayed in AXP as +447890123456. The Raw Data may still show the original format from the source system — this is expected behaviour and does not affect how AXP sends messages.
Q: What does the error "Message cannot be sent with the current combination of To and/or From parameters" mean?
A: This is a Twilio error (code 21612) indicating that the sender number and recipient number are in incompatible countries. Most commonly, this happens when a US sender number (+1) is used to message a UK recipient (+44). SMS messaging between certain country combinations is restricted by Twilio. See Twilio error 21612 for more detail.
Q: Can I use WhatsApp instead of SMS for UK guests?
A: Yes — if your property has WhatsApp configured as a messaging channel, this is a reliable alternative for messaging guests in the UK and across the EU, where WhatsApp is widely used. Check whether a WhatsApp channel is available at your location in AXP.
Q: Who can request a change to the messaging integration?
A: Only a Brand Admin can submit integration change requests. The request should be directed to your Alliants Customer Success Manager. Conversers and Location Admins do not have permission to request integration changes.
💡 Tips: Only Brand Admins can request a new sender number to be configured. If you are a Converser or Location Admin, please escalate to a Brand Admin at your property who can raise the request with the Alliants CSM.
💡 Tip: If a guest is not receiving SMS messages, check whether your property has a WhatsApp channel set up as an alternative — it's often already available and works across borders without the same restrictions.
🗒️ Note: AXP automatically formats phone numbers to E.164 on import. If a number is stored without a country code in the source system, AXP will attempt to add the correct country code. Always verify the number in the guest's AXP profile before troubleshooting further.