Look for your brand / model sevice manual on-line, it should have troubleshooting and testing procedures as well as part # lists and replacement guides.

In the user manual I found this. Searched "Bosch Silence Plus 50 user guide". Since they made multiple models with this name, get the model number off of the sticker on the right side on the door to refine the search.

Large food remnants in the rinsing water not
retained by the filters may block the waste
water pump. 
In this case:
• Disconnect the appliance from the power supply. 
• Remove the filters (see Figures 11-12).
• Scoop out standing water - use a sponge if
necessary.
• Using a spoon, pry off the pump cover (see Fig-
ures 14-15) until it clicks, then grip the cover
and pull upward until it resists and then pull
forward.
• Check inner compartment and remove any for-
eign objects.
• Place cover in the original position, press
down and engage.
• Reinstall filters.