App Phone Verification Fix

My app refuses to accept perfectly valid UK mobile numbers. Every attempt to verify ‑ for example 07711000889 – is met with the “Invalid number” message. I even tested a second number and got the same result, so the problem clearly sits in our validation or API flow rather than with the SIM... (Budget: £250 - £750 GBP, Jobs: Android, API, App Development, Debugging, JavaScript, Mobile App Development, PHP, Twilio)