To register as an Uber user you need to verify your cell phone number. If you did not receive the verification message, try the following:
1. Make sure the phone number is the same as the one on which you have the app installed.
2. Also make sure that the number (excluding the +52 from the Mexican code) is 11 digits. Example: +52 (1 55 2299 3019) for Mexico City.
3. Validate that the country selected before the number is correct.
4. Look for a good Wi-Fi or mobile data connection. Check that they are enabled.
5. Close and re-open the app and try the verification again.