why do my tasks no longer sort according to priority?
giving tasks different levels of priority used to reorder them, this no longer happens. Can I alter this?
Do you mean that you cannot sort by either Date or Priority when in a Project view? The Today or 7 Day View will, if I recall correctly, first sort by date/time, then sort by priority.
When you are in the 'Project view', click on the gear icon (opposite the name of the Project; hovering above the icon will show 'Task actions') and select 'Sort by Priority'.
Please understand that this sort is not 'persistent', in that when you add more tasks, they will not automatically re-sort by date; will will again have to click the gear icon and select Sort by Priority.
There are shortcuts you can use after clicking the gear icon: the keys "s" (to sort by date) or "p" (to sort by priority) if you want to change the order of your tasks., if I recall correctly.