When you click Users tab on XenMobile server receiving error - 500 Server Internal Error (exid:16200BC6AC0-503E3024D00ABC1E4C352FFA2DAD6AC0)

Delete the Duplicate entries from the Database to resolve the issue by Executing the below query in the XenMobile Server Database:
select * from dbo.KEYSTORE where name in (';AgUserAuthCredential=abc@example.com;') order by MODIFICATION_DATE desc
Note: Ensure that you take a back up of database before making any changes 

XenMobile Server gets exception  com.sparus.nps.spi.impl.KeyStoreHandlerImpl.getKeyStore method. Exception could be due to more than one unique certificate found for device under Database.

Problem Cause

Multiple certificate entry found in XenMobile Server

In the Xenmobile Server logs
2018-03-07T08:52:50.881-0500 | C1BA18C0DE305D4C  | ERROR | http-nio-14443-exec-85 | com.sparus.nps.ErrorFilter | Exception (exid:16200BC6AC0-503E3024D00ABC1E4C352FFA2DAD6AC0): org.springframework.dao.IncorrectResultSizeDataAccessException: query did not return a unique result: 2; nested exception is org.hibernate.NonUniqueResultException: query did not return a unique result: 2