The application you are using ran into a problem.
If you let their support team know about this error, please give them a link to this web page as well!
Trying to use (==) on functions. There is no way to know if functions are "the same" in the Elm sense. You can read more about why it works this way here. The root cause may be in your code or in a dependency.
You can get more detailed information on when this happens if you can reproduce the error in dev mode.
Hopefully that helps!