I am attempting to create a custom action for SharePoint 2016 on-prem using the documenation and samples from the SDK.  I have the custom action written and deployed, but when I attempt to use it in a workflow and publish that workflow, I get the following error:  "soap:ServerServer was unable to process request. ---> Failed to publish workflow:<Error><CompilerError Line="-1" Text="Type GetGroupMembership.GetGroupMembershipActivity is not marked as authorized in the application configuration file." /></Error>"

I have placed the following line in the web.config, but continue to get this error:

<authorizedType Assembly="GetGroupMembership, Version=1.0.0.0, Culture=neutral, PublicKeyToken=f4377886582ac619" Namespace="GetGroupMembership.*" TypeName="*" Authorized="True" />

Anyone have any ideas as to what else I might need to do to get this working?