Date Conversion issue in Universe based on HANA calculation View

Dear Experts,

In Hana We have field like schedule payment date as data type as NVARCHAR, we have create Universe based on HANA calculation view.

In IDT business Layer when running the query with schedule payment date as prompt we are getting the error as below,

[303]: invalid date, time or timestamp value: search table error: [6931] attribute value is not a date or wrong syntax;

Can any one help me on this issue, as this is urgent issue we need to resolve ASAP.