Spin cycle spins slowly or not at all. On occasion it will work correctly. I have unplugged the machine, opened and closed the lid 6 times in 12 seconds to reset. I have to turn the tub until the tub gets hard to turn or take most of the clothes out before it will spin. Sometimes very slow and sometimes normal.
Washer belt may be worn. When you add extra weight to the washer with lots of clothing, the belt may be slipping because it is worn. Or if you have a different type of machine, it may be the motor coupler is worn thus creating your issue.