CRM service call returned an error

Hello Team,

We build an ETL using SSIS Integration Toolkit for Microsoft Dynamics 365 and kingswaysoft.

We are getting below error some times.

Can anyone tell what this means is?

Error:

An error occurred with the following error message:"KingswaySoft.IntegrationToolkit.DynamicsCrm.CrmServiceException: CRM service call returned an error: An unexpected error occurred from ISV code. (ErrorType = ClientError) Unexpected exception from plug-in (Execute): SubscriberPostCreatePlugin: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary. (Error Code: -2147220956, Detail Message: An unexpected error occurred from ISV code. (ErrorType = ClientError) Unexpected exception from plug-in (Execute): SubscriberPostCreatePlugin: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.) (SSIS Integration Toolkit for Microsoft Dynamics 365, v10.2.0.6982 - ISServerExec, v11.0.5058.0)System.ServiceModel.FaultException<KingswaySoft.DynamicsCrmServices.Soap2011.OrganizationService.OrganizationServiceFault>     : An unexpected error occurred from ISV code. (ErrorType = ClientError) Unexpected exception from plug-in (Execute): SubscriberPostCreatePlugin: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.".

Thanks!