my recent app button is not working why?

[AC Question]

i was just cleaning my junk files and then bam it stopped working

 

[fixius]

What phone is it? S6 maybe? Common problem with s6. If so..

Settings > Accessibility > Dexterity and interaction > Assistant menu

From here, toggle the switch to "ON". This will create a hovering circle with a window with four panes inside it. If you interactive with the hovering circle it will open a new window in which you have access to the back and recent apps buttons via an onscreen button.