As Per ICAAN rules every Email address must Be verified. It means when a new user register his domain then domain company sent a verification mail to register an email address to verify his email address. But if Register forgets or Ignore to verify email address then after 15 days Domain Company Direct Suspended his domain without any notice.
If you are new register then you must click RAA verification Link when its sent to your email address. A system generates this mail so there is no reason to not come in your email address. Your Email Subject Will be " IMPORTANT! Verify your contact information for your domain name" It will be sent from Alpha Net Sales. Need Just Click Verification link.
Now, what you do if you forget to Click that verification link. Just Find out when you register this email & check that time email inbox & find out that email & Click verification link. If you don't find your Verification link email then go to your domain control panel & there is an option to re-sent verification link. Click that button & sent it again.
If you all those trick was not successful then change your contact email address & try to re-sent again. If you change your contact email address then system sent an email again to your new email address. Now you are attention about this mail so you can't forget to verify. if changing email address already verified customer then its also works. It means if you change your contact email & input already verified customer email address then no need to verify again. Most of Our Domain Reseller have more than one verified the Email address. They can change customer contact email address to their verified email address. But it's not hampering to Domain control panel. Because of its only Change Register Email address.
Note: If your domain is already suspended due to not verification then after verifying its need minimum 12 hours to restore DNS server.