I'd recommend you reach out to Support, note that SMS is only supported in the United States, other locations may vary.
"This feature is currently only available in the United States. If you are in a different country, SMS authentication is still a beta feature, and we cannot guarantee its reliability. Please feel free to test your phone number on the set up page. SMS authentication has been known to work in the following additional countries: United Kingdom, Canada, Mexico, France, Spain, Italy, and Germany."
https://documentation.meraki.com/General_Administration/Other_Topics/Two-Factor_Authentication#Using...