Your page is presumably a data view that needs an object (data record) to display. You cannot connect this type of page directly to the navigation as it cannot be displayed without the correct object type. You have two choices:

1) Instead of opening the form directly, attach a microflow to your navigation item and in this microflow, create or retrieve the data object to be displayed, then open the form passing this object to be displayed in the form.

2) Create a data grid or template grid form to display a list of the objects in a table-like field. This will not need a data object so can be opened directly from navigation. You can then use your original data view form as the drill down to display the record selected in the data grid, or to create new records from the grid.