The two objects in red are the pot handle halves. For some reason when I added the mirror modifier they don't connect.
This is because you Rotated the handle in Edit Mode (or Applied the Rotaion) and it is exactly what you should expect; When not spicified, the Mirroring is done around the Origin of the Object:
An exact way of solving this could be:
in Edit Mode, select a Face of the handle and click the + to create a new Orientation:
Then in Object Mode go to Options and check Affect Only Origins:
Then go to Object:
And then your Object's Origin 'fits' to your Object again. You might need to adjust the mirroring axis:
Don't forget to uncheck the Only Origins Option.