Brew unit and waste unit in place, brew unit is blocked

Have you changed your type of coffee beans or grind setting recently? First of all I would recommend removing and cleaning the brew unit thoroughly (as per cleaning instructions) to eliminate any cleaning issue here...
This is sounds like the flush valve is not working correctly. The flush valve ensures that all unused liquid in tubes is flushed into the driptray and that all solid coffee (dry pellet) goes from the brew chamber into the waste container. At the end of the coffee cycle when the pump stops running, the piston in the brew unit usually moves one last cycle and squeezes the coffee pellet in the chamber one last time and the flush valve operates so that all waste liquid is flushed from the coffee pellet to the drip tray. If your pellet is wet, then this final flush is not working. There may be a blockage in your flush tube or the flush valve may be blocked. These usually block up if you don't run a cleaning tablet through the machine regularly.
My advice is to remove the driptray grill and check that the tubes running into the tray from the brew unit are not accidentally squeezed closed or blocked. Good luck.

https://www.manualslib.com/manual/1038891/Miele-Cva610.html?page=102
Waste unit is not installed OR the
waste unit is not installed correctly
•Re-install the waste unit
•Check magnet on rear of waste unit
•Check brew unit present switch

The standard instructions are ... remove the waste container, water container & ground coffee container. On the front of the Brew Unit is a vertical black lever with a grey press button at bottom. Press this button and turn the lever clockwise. Then press the release catch that holds the brew unit as base and pull the brew unit. If Brew Unit is still stuck then its likely that the Unit State is not in the 'home position' and if this has occurred then its likely that that an error code would be showing. Regards

It is because the brew unit is not in the "rest" position. Somebody plaid with it or there is a malfunction with the brew unit so it is not in the initial position. Post a picture of the brew unit in place (without the waste container) and I will make my best to help you.

The brew unit has lose parts on left-hand-side, wiggle them up and down. Put the waste unit back, switch off the machine and then turn it on (pull the cord). It worked for me!!!

First clean the screen and tube on the brew unit, then lube the guides/gear grooves on the brew unit, also lube the o-ring(big red one). Then that should take care of it. You can also try backwashing/degreasing the brew unit if the machine has a preground chute.

hey just manually pull down brew group internals till neutral reached push waste flap in to lock position seen on rear tab and leave brew group unit and water tray / waste bucket out, place a small magent / metal on bottom rear left of inside panel ( check waste unit for small metal tab and align magnet on rear where this sits, at the same time then place small magnet where door tab hits plastic sensor in machine roof then power off and on machine resets to neutral remove magnets insert brew group and waste trays and u should be done. WARNING !! DO NOT ATTEMPT WITH BREW GROUP IN PLACE KEEP RESETTING MACHINE IF YOU FAIL AS IT SETS A FAULT AND WILL ENDLESSLY SPIN DRIVE

check small switch behind brew unit in machine maybe your brew unit dont touch switch.

Check the shower screen on the brew unit.

Try this, check brew unit on it you will see a small arrow, this has to be pointing at the letter N, whisch is near the handle. Remove the drain tray and dreg tray, check the rails for the brew unit make sure there is no coffee on it, then slide unit in place.