Hello Rachana BP,
Please check whether you are using the same version in different instance, primary cause can be data issue if issue is coming in only one instance.
You can add some log on each scheduler and can identified which one is causing issue and then accordingly you can check that microflow.
Also, you can download the data from instance where it is causing issue and run that database using PG admin in local if your organization allow that, and you can easily fix this issue.
I would double check your running now microflows to see is some scheduled event is still running. And a restart of the environment might also help.
Regards,
Ronald