Overdue task emails suddenly stopped sending?

Question

I have a 2013 workflow for Document Approval, and as part of the workflow, a task process is started with a SharePoint group, and sometime within the past 1-2 months, overdue task emails have stopped sending out... but no changes have been made to the workflow.

I have other workflows with task processes that send out overdue emails properly, the only difference I see between them is the one that no longer is working has an "App Step" (but after the task process).

Any settings I should check to help figure out where this is getting blocked up?

Update: The issue is taking place in Document Libraries, but not Lists as far as I can tell.

Answer 1

Let's investigate your issue by doing the following:

First, you have said the overdue task mail was sent within the last 2 months and it stopped working now! Also, you made sure that the other workflows are sending email properly!

That generally means there is no issue in the pre-configured email setting for your tenant

BTW, Unlike SharePoint OnPrem, you can't manage outgoing email setting in SPO

Second, you have said the only difference is the APP Step

I don't think it causes such issue especially since it was present, and the overdue email was sending properly as you have said!

App step is used to allow the workflow to be authorized with its identity as a Full Control and ignore the current user permissions.

This is will ensure that the workflow will be executed successfully in case the current user has no permissions. Read more at Workflow was Suspended with Unauthorized HTTP / Elevate Workflow permissions in SharePoint

Third, you have updated your question and said The issue is taking place in Document Libraries, but not Lists!

Actually, the Start Task Process action doesn't care if it is a list or library? additionally, there is no overdue email setting in both!

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Let us sum up the previous points by ignoring the imaginary causes and focus on the real causes.

• This issue is not an email issue.
• This issue is not related to APP Step.
• This issue is not related to if it's library or list!
• This issue is related to the workflow itself by 80%.

Let's focus on the last point,

• Check the last modified date for workflow, maybe it recently modified!
  • Open SharePoint Designer > Workflow > check the modified date column for workflow.

• Whether the workflow has been modified or not, try to:

  • Check all Task Process actions, and Make sure that the task overdue send email is checked and its recurrence settings are set properly as you prefer.
  • Save, and Publish.

  

  Don't forget to check also the Completion Criteria settings, maybe the overdue condition has not been met.

• Try to create a new workflow with only task process action on the current document library and stop the current one to make sure that the issue is not related to the document library.

• Also, try to create a new workflow that simulates the current workflow steps on another Document library to make sure that the issue is not related to the workflow.

Answer 2

I've awarded the bounty to @Mohamed since he led me to find the solution.

Document Library Tasks no longer pull due dates from the task list

I had the workflows set with Due Date = "" and set the date to default to [Today] + 2, which had been working properly. You now need to use this calculation:

and set the output as the Due Date for the task.

Answer 3

There has been recent sec update to the .net framework that makes some of the workflows to fail:

https://www.skylinetechnologies.com/blog/skyline-blog/october_2018/sharepoint-workflow-failed-to-start

There is official guidance from MS how to resolve it: https://support.microsoft.com/en-us/help/4465015/sharepoint-workflows-stop-after-cve-2018-8421-security-update?ranMID=43674&ranEAID=je6NUbpObpQ&ranSiteID=je6NUbpObpQ-kWsEtr2UDwqhwK3zpB9cQQ&epi=je6NUbpObpQ-kWsEtr2UDwqhwK3zpB9cQQ&irgwc=1&OCID=AID681541_aff_7795_1243925&tduid=(ir_559fcf05N4ea222cdbf5db2bedf431375)(7795)(1243925)(je6NUbpObpQ-kWsEtr2UDwqhwK3zpB9cQQ)()&irclickid=559fcf05N4ea222cdbf5db2bedf431375

you need to add folowing lines to your webConfig:

<authorizedType Assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" NameSpace="System.CodeDom" TypeName="CodeBinaryOperatorExpression" Authorized="True" /> 
<authorizedType Assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" NameSpace="System.CodeDom" TypeName="CodePrimitiveExpression" Authorized="True" /> 
<authorizedType Assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" NameSpace="System.CodeDom" TypeName="CodeMethodInvokeExpression" Authorized="True" />
<authorizedType Assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" NameSpace="System.CodeDom" TypeName="CodeMethodReferenceExpression" Authorized="True" />
<authorizedType Assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" NameSpace="System.CodeDom" TypeName="CodeFieldReferenceExpression" Authorized="True" />
<authorizedType Assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" NameSpace="System.CodeDom" TypeName="CodeThisReferenceExpression" Authorized="True" />
<authorizedType Assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" NameSpace="System.CodeDom" TypeName="CodePropertyReferenceExpression" Authorized="True" />