Machine turns off too soon

it sounds like you don't have enough water come blockage or luck of incoming water if you have a filter in the water tank remove it and try again

There is another process to get into descale mode on some 7.1 machines. I got this from Illy Support:
Descale Cycle
• Turn off machine
• So the usual filling if container with descale fluid
• Turn machine on and within 15 seconds from power on – press and hold in the big cup
button until it gives 4 acoustic signals and then release your finger.
• The big blue cup button should now be flashing
• Press the big blue cup button once – the machine will now dispense water intermittently
from the coffee group head and the steam arm and the steam and coffee button will be
flashing alternately
• Once the descaling cycle has completed it will give out a long acoustic signal
• The coffee button will continue to flash
Rinsing Cycle
• Remove the water tank – wash out and fill with clean fresh water just over the MAX level
• Empty the container holding 1 litre of water and reinstate back under coffee group head and
point steam arm in container.
• Press the flashing big cup button once
• Water will again dispense intermittently from group head and steam arm
• An acoustic signal will sound out as soon as the rinsing cycle is complete.
• The Big Blue coffee button will be steadily lit
• Remove 1 litre container.
• Remove water tank – clean and refill with clean water

–red light should now be off and ready to make coffee

To programme the quantity you would normally hold the button down continuously for as long as it takes to fill your cup to the required level. Next brew you make should require a single touch & release it should then flow through as much water as the previous cup and then stop automatically. If it's not holding the programme I can't see any harm in holding the button down until the cup is full.

WHAT IS A FULL CUP FOR THE MACHINE? Just because "your" cup isn't getting filled up doesn't mean the machine is broke. You may be using too large of a cup.

When you purged the lines or tubes retained debris and need full purging and flushing.

Had the wrench icon problem on a used Talea Touch that I bought.
Don't know how it started with the previous owner.
Solution - cleaned compressed coffee grounds from the grinder discharge. You need to manually spin the motor to clean all grounds from the rotation discharge gate.Also needed to probe and press the electrical connections to the motor. The brush spring and capacitors are press connected.
This solved the problem.
I've owned abnd repaired many Saeco machines. They are poorly designed and over priced.
None the less the majority of their problems can be fixed by simply cleaning the components.
Enjoy
MDR

If you read your manual, it explains how to program the machine to allow the amount of water that you want to have per cup.

Remove the brew basket and water defuser (sprinkler head) it should come off with a 1\2 turn.
Place your measuring pitcher or empty pot in place.
Turn the main power switch off in back of unit.
Press and hold the Brew(full pot) button.
While holding the Brew(full pot) button turn the main power button in back to on.
Once the red light flashes over the Brew(full pot) button release it, then press it once to start the brew cycle.
Let it flow until desired level in pot or measuring pitcher.
Press the Brew(full pot) button once to Stop.
Press the Brew(full pot) button once again to lock the settings into memory. Memory will store the settings even if machine is unplugged.
Half pot button is automatically set.

I use distilled white vinegar, but you can use specialized coffee cleaners with this model:

Descaling
Descaling 11
Descale your Tassimo machine every three months to keep it
operating at full potential.
1 Descaling products are widely available from stores selling coffeemakers and espresso
machines. Only use a product intended for descaling. Mix the descaling product
directly in the water container, following the instructions provided on the descaling
packaging. Replace the water container on the machine.
2 Place a large cup or mug on the cup stand, insert the cleaning disc, bar code down,
and close the brew mechanism. When the AUTO light illuminates, press and release
the start/stop button. The brew cycle will fill the machine with descaling solution. Empty
the cup and let the machine stand for 15 minutes.
3 Open the brew mechanism and close it again, leaving the cleaning disc in place.
When the AUTO light illuminates, press and release the start/stop button. When the
machine stops running, empty the cup, and let the machine stand for 15 minutes.
Repeat this step two more times for maximum descaling effectiveness. Discard the
remaining descaling agent from the water container, rinse it thoroughly and refill
with fresh, cold water.
4 Open and close the brew mechanism again, leaving the cleaning disc in place.
When the AUTO light illuminates, press and hold the start/stop button to flush water
through the machine. The MANUAL light will flash. When the cup is full, release the
start/stop button, empty the cup, and replace it on the cup stand.
5 Repeat step 4, flushing clean water through the machine in the same manner and
emptying the cup as it fills. To ensure that all the descaling solution is completely rinsed
away, flush two full water containers through the machine before using it again.

Try flushing the machine by filling the water tank with water and then pressing both the one cup and the two cup buttons at the same time (make sure to put a big enough bowl under the spout). If this doesn't work, give Senseo a call: 1-866-4SENSEO. They should be able to help! Good luck!