The most recent inspection came after Universal saw large crowds over the holidays.
Loews Hotels said it was canceling the event, citing the mob attack on the U.S. Capitol.
Invites were sent days after Universal's parent company cut off political donations to Hawley and others who voted to block certification.
Knott's will now extend passes into 2022 for each day the park remains closed.
The event will see the return of the Mardi Gras Tribute Store, but larger concerts and parades will not be held thanks to COVID-19.
2021's new attraction lineup ranges from record-setting roller coasters to an immersive hotel experience.
Nintendo legend Shigeru Miyamoto hosted a tour that showed off never-before-seen elements of Super Nintendo World.