I’ve installed HP ALM synchronizer 12.53 SP2 and trying to synchronize defects with TFS 2015. Link established sucessfully and synchronizer is able to connect to both end points sucessfully.
But while trying to fetch schemas for mapping below error is displaying. I tried to search in HP forums and microsoft forums for a fix to this problem. Not much information available about this issue.
Please help.

*ERROR #1- server.link.FAILED_TO_READ_EP_SCHEMA : Failed to read endpoint schema. Error: server.link.FAILED_TO_READ_EP_SCHEMA : Failed to read endpoint schema. Error: server.RemoteExecService.UNHANDLED_EXCEPTION : Unknown exception type is caught: com.hp.qc.synchronizer.adapters.exceptions.FatalAdapterException: buildEntitySchema: disconnected **Error converting value "System.Security.Principal.WindowsIdentity;S-1-5-21-3391493652-317867085-22542440-144021" to type ‘Microsoft.VisualStudio.Services.Identity.IdentityDescriptor’**. Path ‘authenticatedUser.descriptor’, line 1, position 168….ERROR #2- server.link.FAILED_TO_READ_EP_SCHEMA : Failed to read endpoint schema. Error: server.RemoteExecService.UNHANDLED_EXCEPTION : Unknown exception type is caught: com.hp.qc.synchronizer.adapters.exceptions.FatalAdapterException: buildEntitySchema: disconnected Error converting value "System.Security.Principal.WindowsIdentity;S-1-5-21-3391493652-317867085-22542440-144021" to type ‘Microsoft.VisualStudio.Services.Identity.IdentityDescriptor’. Path ‘authenticatedUser.descriptor’, line 1, position 168…
ERROR #3- server.RemoteExecService.UNHANDLED_EXCEPTION : Unknown exception type is caught: com.hp.qc.synchronizer.adapters.exceptions.FatalAdapterException: buildEntitySchema: disconnected Error converting value "System.Security.Principal.WindowsIdentity;S-1-5-21-3391493652-317867085-22542440-144021" to type ‘Microsoft.VisualStudio.Services.Identity.IdentityDescriptor’. Path ‘authenticatedUser.descriptor’, line 1, position 168..
ERROR #4- buildEntitySchema: disconnected Error converting value "System.Security.Principal.WindowsIdentity;S-1-5-21-3391493652-317867085-22542440-144021" to type ‘Microsoft.VisualStudio.Services.Identity.IdentityDescriptor’. Path ‘authenticatedUser.descriptor’, line 1, position 168.
ERROR #5- AutomationException: Error converting value "System.Security.Principal.WindowsIdentity;S-1-5-21-3391493652-317867085-22542440-144021" to type ‘Microsoft.VisualStudio.Services.Identity.IdentityDescriptor’. Path ‘authenticatedUser.descriptor’, line 1, position 168.*