crm 2011 workflow email issue

experienced and issue with a crm 2011 workflow failing to send and email, and remaining stuck in the status reason 'waiting for resource'. it seems the cause was from changing the cc, and bcc fields. there are other workflows that send emails with no issue.. so it it likely not the email router message Cannot create the given type without the required parameters. Plugin Trace: [Microsoft.Crm.Workflow: Microsoft.Crm.Workflow.Activities.EvaluateExpression] [EvaluateExpression] Error Message: the work around i found here proved insufficient https://rule30.wordpress.com/2014/04/10/fix-microsoft-crm-crmexception-cannot-create-the-given-type-without-the-required-parameters/ and ultimately ended up recreating the workflow