Samsung Galaxy S6 red horizontal line appears then phone freezes

I have a Samsung Galaxy S6 (G920F) which was in contact with water, and the left screen key (multitasking) sometimes blocked and phone worked itself. I opened the phone and in the charging connector where the sensors are placed, the one which did the problem, was with dirt (water, white etc), cleaned it and worked quite good for a night. Then, today the phone started freezing, i turn it on, and after seconds it shows a red horizontal line in the top of lcd then phone hangs (freezes and turns off).

where the problem might be, do you have any suggestions ?

thanks in advance