First, check your spam. It is possible that the confirmation e-mail ended up there. Is it not there?
You may have made a typo in your e-mail address. If you are logged in (via my.guts.tickets) you can view your e-mail address at 'Your profile' and adjust if necessary. If you have changed your e-mail address, you will receive all future GUTS e-mails there.
Information from the e-mail:
Then, of course, you have still missed the confirmation e-mail. No panic: your ticket will not be sent by e-mail. Here is all the important information from the e-mail:
Your tickets will be kept safely online in your GUTS account, which you can open on your mobile phone. It is recommended to do this ahead of the event, in order to save time and avoid long lines. You can always find your tickets on my.guts.tickets or via our app.
Install the GUTS tickets app on your phone:
The easiest way to always have your smart tickets within reach.