Why my apps are not getting locked?

[AC Question]

I am using nexus 4 and since the last update 5.1.1, I am unable to lock my apps. I have an app lock application in my fone which enables lock on selected apps. But now its not working. I tried uninstalling the application and then reinstalling it but still having the same issue. it is really upsetting me. I have also tried restarting my fone so that it might work but NO! its not!. I have also tried to install another app lock application but, not working. Kindly help me regarding this issue.

 

[UJ95x]

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