Hello @Abdullah Ibn Ahammed SMS capabilities depend on the phone number you use and the country/region that you're operating within as determined by your Azure billing address. Numbers can only be purchased on "eligible" Azure subscriptions and in geographies where ACS is legally eligible to provide them. Since your billing address is in India, I see that India is currently NOT present in the set of geographies where ACS is able to provide the service and thus SMS as well. As a result, for your specific client in the UK, you'll need to have a phone number and an Azure billing address in the UK (or another supported region). You can find the list of supported regions by pulling the drop down on this page -- https://learn.microsoft.com/en-us/azure/communication-services/concepts/numbers/sub-eligibility-number-capability
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