Ruby Freeform Projects consistently returns ArgumentError in Posts#index

This is the same error as in this post:

https://discuss.codecademy.com/t/7-5-update-a-destination-i-use-form-for-error/84218

Except that my parameter is not spelled incorrectly. I have encountered this error in both the Innovation Cloud and Threadly Projects after resetting multiple times. My code is exactly the same as in the hints and in the Project Walkthroughs. Would really appreciate a mod or another user helping me out. Thanks.