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Code Fix: An error occurs on a workflow when an Email step recipient value is empty


Issue Description

When an Email step contains an empty value in the TO line of the recipient mail, the workflow will go into an error state and will not continue.

Error Message

The following error occurs and is visible in K2 Management: “SourceCode.Workflow.Shapes.Execution.Mail.EWS: Exchange error code: ErrorInvalidRecipients Exchange error: Microsoft.Exchange.WebServices.Data.ServiceResponseException: At least one recipient isn't valid., A message can't be sent because it contains no recipients.”.


The fix is available in the following K2 versions:

K2 4.7 December 2019 Cumulative Update K2 Five (5.0) December 2019 Cumulative Update K2 Five (5.1) November 2018 Cumulative Update K2 Five (5.2) May 2019 Cumulative Update K2 Five (5.3) April 2020 Cumulative Update K2 Platform Classic (5.4)
X X Fix Pack 36 Fix Pack 41 Fix Pack 6 Fix Pack 1
  1. Ensure you have the correct K2 version and/or Cumulative Update installed. See KB001893 to see what Fix Pack level you have installed.
  2. Download the latest Fix Pack using the links in the table above for the version you require.
  3. Install the Fix Pack to apply the fix.