Signup IRL Verification: SMS
The final step in the signup process is the "IRL verification" where we try to make a connection to something less virtual than an email address. The easiest way to pass this step is to receive an SMS with a verification code.
It's important that you get the format of your phone number correct to receive the SMS. Include the country code and area code (cellphones usually have their own "area" code always included in the number). Don't enter any spaces or characters such as '+', only digits. Remove any leading zeroes in the country code and area code.
For example, let's say your country code is +046 and your area code is 0708. The number you should enter is: 46708xxxxxx
List of country calling codes at Wikipedia