Have you found yourself in a bit of a loop when trying to connect Instagram to Timehop? This is a known issue for not only Timehop, but any 3rd-party app that connects to Instagram.
It's related to a security feature from Instagram that flags any "suspicious login attempt"--in this case, it just means anything outside of your normal login behavior--and requires you provide further verification to prove you are you.
When this happens, you will be prompted to verify who you are by entering a secondary code sent to you via a phone number or email. Unfortunately, once the you go through this flow, the authentication flow to Timehop must be restarted. To move forward, tap "Done" and then try to login again. This should do the trick! If you continue to have issues, please let us know!