Sump/Ejector Pump

[mounty68]

I have an ejector pump system in my basement, as the city’s sewer lines are higher than my basements’. It has a check valve just outside the sump basin on the outflow pipe.

The problem is, that my pump is no longer working very well. Sometimes when I have used the toilet in the basement, or the sink, and I have not heard the pump eject the sewage/water, and the soft click/thump of the check valve closing, I have to go over and hit the check valve/pipe a couple of times, and then it will kick on.

My question is, is this a problem with the pump or the check valve ?

Thanks a lot