integrating sandbox web part to master page sharepoint 2013

how do i integrate sand box web part into the master page??

i tried many things and these are working working with farm solution web part but its not working for sand box solution web part,it keep showing me the error as

ExecuteRequestInSandBox call failed. System.NullReferenceException: Object reference not set to an instance of an object.

at Microsoft.SharePoint.WebPartPages.BinaryWebPartSerializer.Serialize(PersonalizationScope scope, BinaryWebPartSerializerFlag binaryWebPartSerializerFlags, BinaryWebPartSerializerWriter writer)

at Microsoft.SharePoint.WebPartPages.BinaryWebPartSerializer.Serialize(SerializationMode mode, BinaryWebPartSerializerFlag binaryWebPartSerializerFlags, BinaryWebPartSerializerWriter writer)

at Microsoft.SharePoint.WebPartPages.SPUserCodeWebPart.EnsurePersistedBlobsMatchPropertiesCollection()

at Microsoft.SharePoint.WebPartPages.SPUserCodeWebPart.GetWebPartDataForRemoteCall(Object& viewState, Object& controlState)

at Microsoft.SharePoint.UserCode.SPUserCodeWebPartRemoteExecutionHelper.ExecuteRequestInSandBox(HttpContext context, SPWeb web, SPWebPartManager manager, SPUserCodeWebPart userCodeWebPart)

Thanks in advance