Siemens EQ.6 plus s100

Hello everyone on this great forum!
I have a Siemens EQ.6 plus s100. If the machine is unplugged and completely cool/cold, it works fine after start-up for all kinds of drinks up to about two cups.
BUT at the last cup you can feel that the machine gets very hot at the top and there is also much more steam on both the side and the bottom at the second cup.
After this, the machine refuses to do anything more, not even cleaning the milk system works.
If I unplug it and let it cool for approx. 15-30 minutes and it works as usual again. Also don't get an error message that it's overheated, but that's just my amateur guess.

Has anyone here experienced something similar or has an idea of ​​what it could be?

The machine has made about 2000 cups.
In the component test it says "HE on 1400W, 3s, Ts:199 C"

Thanks for any input I can get!