You must be able to receive phone calls and SMS to the phone number you are trying to verify.
You must have any call-blocking settings, apps or task killers disabled.
You must have a working Internet connection through mobile data or Wi-Fi. If you're roaming or have a bad connection, verification may not work. Try opening www.whatsapp.com on your phone’s Internet browser to see if you are connected to the Internet.
How to verify
Enter your phone number:
Choose your country from the drop down list. This will automatically fill your country code on the left.
Enter your phone number in the box on the right. Don't put any 0 before your phone number.
Tap Next to request a code.
Enter the 6-digit code you receive via SMS.
If you didn't receive the 6-digit code by SMS
Wait for the progress bar to finish and retry. The wait may take up to 10 minutes.
Don't guess the code, or you will be locked out for a period of time.
If the timer runs out before you receive the code, an option will appear to request a phone call. Choose the Call me option to request the call. When you answer the call, an automated voice should tell you the 6-digit code. Insert that to verify WhatsApp.
Note: Depending on your carrier, you might receive charges for SMS and phone calls.
If you are having issues verifying, please try the following:
Reboot your phone (To reboot your phone, turn it off, wait for 30 seconds, and turn it back on).