Could be a few reasons for this.
The timer may be bad or you may have a clog in the hoses that run to or out of the water pump, or the water pump may be bad.
Can you hear the pump running when the washer is on the drain cycle? If not, then the pump may be bad or the timer isn't going into the drain/rinse cycle.
If you can hear the pump, then it is more likely something clogging the pump or one of the drain hoses. Such as a small sock.
The timer may be bad or you may have a clog in the hoses that run to or out of the water pump, or the water pump may be bad.
Can you hear the pump running when the washer is on the drain cycle? If not, then the pump may be bad or the timer isn't going into the drain/rinse cycle.
If you can hear the pump, then it is more likely something clogging the pump or one of the drain hoses. Such as a small sock.