You probably shouldn't try to verify your ID online just yet.
Keep an eye on the "Where's My Refund" page for at least a couple of days.
If you don't see that your return has been accepted within a few days, you should probably call the toll-free IRS Identity Verification telephone number shown in the 5071C letter, before attempting anything else online, so that an IRS support person can best advise your next move.
