Error occurred in Document Record approval rules page.

Summary:

I was working on Approval Rules under Manage Document Records in Transaction Console. I have written the rules for specific document and tried to save and submit it, but the system is throwing an error repeatedly.

To resolve the error, I managed to delete the rule and tried to save it. Still the system is showing the same error.

I would appreciate to provide a suitable solution to come up with this issue.

For your reference, I have provided a picture.