Offline error when trying to save a record

 My user gets this error when in offline mode on CRM for outlook and ideas ?

Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: An unexpected error occurred.Detail:

<OrganizationServiceFault xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/xrm/2011/Contracts">

  <ErrorCode>-2147220970</ErrorCode>

  <ErrorDetails xmlns:d2p1="http://schemas.datacontract.org/2004/07/System.Collections.Generic" />

  <Message>An unexpected error occurred.</Message>

  <Timestamp>2016-10-28T08:14:49.4515131Z</Timestamp>

  <InnerFault i:nil="true" />

  <TraceText>

[Microsoft.Crm.ObjectModel: Microsoft.Crm.ObjectModel.SyncWorkflowExecutionPlugin]

[a45d8390-3fb4-e511-8121-fc15b4262f48: ]

</TraceText>

</OrganizationServiceFau