Alexus

My machine is only 18 months old. Hotpoint Aquaris (WMF720) showing F05. Checked the filter. All clean. No blockage. Disconected from the drum all clean there too. Same with the outlet hose. All clean. No blocakage. Works fine at SPIN cycle. However, washing machine still stops at RINSE cycle (when things are put in for wash), showing fault F05. Any other suggestions?