You have rotated/scaled your model in Object mode and didn’t applied those transformations, so it throws off many tools calculations (you wouldn’t had this if you did the rotation/scaling in Edit mode).
You can see that by pressing N and noticing that the X/Y/Z scales are not 1.0/1.0/1.0 and the X/Y/Z rotations are not all 0
So still in Object mode, select the object, press CTRL+A -> Rotation&Scale (or click on Object -> Apply -> Rotation&Scale) and it will fix your problem.