@CGMRUNAL 

How was this error solved?  Just by turning on the service or something else?

But where we find Machine learning service turn on/off option

It is a separate service that must be started outside of IFS Cloud as part of the various pieces of the application.  Your database administrator would know it, it isn’t a user setting.

I was trying to figure out why you marked your own reply as the best answer if the problem isn’t solved?

By mistake I click on best answer 

@CGMRUNAL 
I may be late here but just checking if this issue is sorted or set as resolved by mistake.

@ShawnBerk  You are right, this is not and end user setting but something for the PSO/Machine learning configuration team depending on the IFS Cloud version.
In IFS Cloud 23R1 or prior versions, below is the page that needs to be configured.
 

From 23R2 onwards, Instead of “Scheduling optimization and machine learning configuration” page , ML configuration can be done in “Machine Learning Configuration” page.