encryption of configuration parameter disabled

Hi All,

I Can not encrypt configuration parameter.

Check box is disabled, do you know why this is disabled.

I chekced in my other OIM instances and I see checkbox in enabled.

https://1drv.ms/u/s!At2ViqLAc9HpyDqSdwILWg2QvIJq?e=TxlikD 

OIM version is 8.1.5.

Is it not allowed in 8.1.5?

Thank you.