Creating a list workflow on SharePoint Designer 2013. My workflow shows no errors but after attempting to publish, comes back with "Errors were found when compiling the workflow. The workflow files were saved but cannot be run." Additional details stated, "(0, 0) Activity 'ID8090' validation failed: Property "Condition" has invalid value. Condition expression is invalid. The field "substring" on type "Microsoft.SharePoint.Workflow.ROOT" does not exist or is not accessible.)"
What is or where can I find this error to fix it?