My softener drain in my washer will not release the softener on the rinse cycle. What can I do to clean this?

When I put the softener in the bin on the right it just never releases. It will be there at the end of the cycle. What am I doing wrong? Yes it is an old washerMy softener drain in my washer will not release the softener on the rinse cycle. What can I do to clean this?
The holes in the dispenser are plugged with thickened or dried softener. It's very common with old or new machines, especially if they are used continuously for light or medium loads. You can clean and flush the dispenser and outlet holes to make it like new again.