IOS Foundations Learning App fatal error in @main

Hello. I am running XCode 12.5 and have recently finished the Learning App. I am having an issue whenever I launch the program in the simulator. The program launches normally, but once I click into a lesson I receive this error:

Bizarrely, this error does not occur when I use the preview.
Thanks for any help.

@jackwill31

Hi Jack,

Welcome to the Code Crew community.

One of the messages in your Console is telling you that there is an error with a connection to the server where you are storing your data2.json file.

This may be causing something to be nil when there was an expected value.

Have you been running the project in the simulator progressively in each Lesson as you build it or have you been relying on the Preview the whole time?