I am having trouble verifying my phone number

The country code of the phone number is determined by the location selected from the "City" drop-down menu. Please be sure to enter your state and zip code as well.

One thing to note is that not having a verified phone number on the platform doesn't prevent you from participating. The phone number is used to send you notifications and reminders, but you are still able to participate without a phone number there (you will receive email reminders and notifications).