Hello Raphael,
Hope you're doing well.
As you can see, UpdateTasks action receives a Tasks Record as a Data Type.

So in this action you need to pass a correct Data Type as an Input Parameter.
It seems that you're passing the Name of one of the Input Elements that are created in your Form:

But you need to use the variable instead. And in this case, you want to use the entire Record (which is associated to your Form), not only the TaskName attribute.
So, according to your image, it should be something like:
GetTaskById.List.Current.Tasks
Resulting in this:

Hope that this helps you!
Kind regards,
Rui Barradas