"wborst".....Many of the electric toilets have a knob at the back that will let you turn it (screw type) and open the valve in the toilet manually. You probably have an Aries II toilet. They have two push buttons on the side, one to add water and the other to flush.
If you turn the knob on the back, you can open the drain valve all the way. Put on a glove, reach in and clean the seal. Often there is debris caught in the seal. Once clean, turn the knob all the way back until it stops and check how your seal is now working.
The addition of electric toilets and porcelain bases have just made the camping experience better. They're easier to use than pushing pedals and are pretty trouble free. Many newer coaches don't directly drain over the tanks anymore, so some of the toilets even have built-in macerators to pump the fluid to the tank.
Don & Mary
2019 Newmar Dutch Star 4018 - All Electric
2019 Ford Raptor Crew Cab