Bosh dryer model WTW84360IT/02

Hi kindly community,

I have Bosh dryer model WTW84360IT/02 that has a this issue: start the cycle and after a bit of time (it's not always the same may 10, 15 20 min ) the display start blinking with a code I believe Cln (see photo attached) and after some blink the dryer turn off and if I touch the on/off button nothing happened, only if unplug and plug the power cable and then press on/off button the dryer turn on but after some time the same issue come up.

I personally deep clean the heat exchanger 2 months ago and at the beginning I did have any issue.

Thank you in advance for the support
Simone