SharePoint Sequential Approval Workflow is working fine in debugging stage but getting an error when deployed

I have developed a sequential approval workflow, which is working fine while I am debugging it.

But once I deploy the workflow and start testing it again, I get inconsistent results. Some times it works fine and other times, I get the below error –

“Error Occurred”

I am not sure as to what could be the root cause of the problem.

I have tried with testing the same scenarios (while debugging and after deployment) to eliminate any variability in testing.

Any help is greatly appreciated.