WT -> SEO -> Import New Rates ->Error while importing a rate with "Cobra Rate" set to Yes.

1] Login to the application on local environment using following URL:
https://wt-stage.harbinger.in
2] From Home page search and select a company for which testing needs to be carried out using "Search Company" section.
3] Click on "Ben Admin" menu.
4] Click on "Customizer" icon from left navigation menu.
5] Click on "Rates" link which is submenu of "Customizer", user gets navigate to "Rates" details page.
6] Click on "Import" button displaying at top right hand side of the "Rates" page, the "Rate Import" window gets poped up, click on “Add New Rate” tab.
7] Download "Health" template from benefit template dropdown.
8] Set COBRA rate value to Yes in the excel sheet.
9] Upload and try to import this rate.

Actual Result:
Error pop up "Server encountered an internal error....." is displaying.
Expected Result:
Rate should be get imported without any error when COBRA Rate value is set to Yes.
Refer attached screenshot for more details.