This is actually 2 issues both caused by the same thing, pstmrk.it. I can't access the link for the bundle I purchased because pstmrk.it is being blocked as malicious. also I prefer to access games via the itch.io app, but the app can't open pstmrk.it links so it just redirects them to my browser instead.

pstmrk.it is the domain owned by one of the email sending companies we currently use, https://postmarkapp.com/. We can confirm they are not malicious. You should allow access to the link on your mail client or browser.

The app manages game ownership completely separately than your email. You’ll have to ensure your purchase is connected to your account then you can access the game directly in your library through the app. No links necessary.