Looks like this is a persistent problem that the developer has not fixed. Lot's of posts about this issue.

I can log in. Then assures me I will receive a verification code, which never arrives. I can access the sheet music. I cannot have multiple plays on the midi player.

I'm sorry you've had difficulties with this. A small percentage of the emails we send out seem to get lost en route, we are still looking into the issue, but haven't yet been able to resolve it. I've emailed your separately to sort out the problem with your account.