Can't activate my android device manager

[edzhusrolavs]

For some reason, I can't activate android device manager...
It is - Settings->Security->Device Administrators.
When i click to activate it just goes back to the previous screen unchecked.

I have Samsung galaxy s4 or gt-i9515 running the lollipop release.*

Sorry for my bad english, im from Latvia.
Thanks

Posted via the Android Central App

 

[B. Diddy]

Welcome to Android Central! Try going to Settings>Security>Clear Credentials. Now try again.

Are there any other Device Administrators listed there?

 

[Shane English]

Clear creditentials is greyed out... Any help?

 

[MIKEYKID11]

Several threads on this with people unable to activate various administrative permissions.. Device Manager, Lookout, etc..
anyone ever find a clear answer..?