Miele PT 7136 Vario Alarm beeping?

Hello, I have a Miele tumble dryer PT 7136 Vario. The alarm goes off constantly (about every 10-15 minutes), and the message is "Clean out airways, clean the fluff filter, check ducting". The filter barely has any fluff and there is no blockage. I have tried disconnecting the vent, connecting it to other holes, making it shorter, but the only way to stop the constant beeping seems to be to remove the vent and keep the hole open which isn't really a solution.

I have switched the option for the "clean airways" message to off and to normal but it keeps giving the alarm & message.

Is there a way to completely disable the alarm or do you know what the problem might be?