Who did the email come from? I got one about a week after tickets went on sale from MRS Sandbox but thought it was junk as I didn't think we would get the code until today, but kept it anyway. Today thinking that was it I opened it and see it was from livenation/ticketmaster. So I clicked on the link and get an error message saying:
Something went wrong. Perhaps we can help.
We are an email service provider, and email sent from tr*****.com (strikeouts mine) comes from our subscribers. So we're guessing one of our subscribers sent you a message with this link in it. Sorry for any tr