Administrator was not able to create any cases

Product/components used and version/fix level:

Agileapps 10.13

Detailed explanation of the problem:

Unable to create cases.
We have set of rules on the Case creation form. based on the option users selects on the radio button we’re enabling/changing/showing an additional tab.
Now, users from the respective group was able to create the case by selecting the respective option (Y/N). However Administrator was unable to create cases when we opt for Y.

Error messages / full error message screenshot / log file:

Getting error as below
However, there is no error message printed on the logs nor on the console.

Question related to a free trial, or to a production (customer) instance?

customer instance