Good evening My name is Ivor
I hope I can give a pointer to your problem. I have looked at the manual. The symbol you describe is shows that there is low conductivity from the washing to the sensor. If you have the manual then the page you require to adjust this is on page 14. If you dont have the manual you can find it on www.usermanualguide.com/zanussi.
You may need to adjust the dryer upwards to the next level.
I hope that this will assist you