ultiVS

Hi, I am new to this but have managed to successfully print for the first 2 weeks after purchase of ultimaker 3. Now I have levelling isssues. It repeatedly fails active levelling. In manual levelling, I rotate the wheel for back position then it comes forward to the right asking to space 1mm away but I am as far away as can be using the screw and the nozzle is still touching the plate. Same with the left position. Can anyone advise please?