I have 3 levels of approval in Nintex workflow. All approvals is approved then it is failing into log to workflow history list. Even we are writing static text in to Workflow login history, There is no custom value to write in login history though It is failing and giving following error. Also we restart same workflow on that document it is working fine.
Nintex.Workflow.NWActionExecutionException: Failed to log to history list. ---> System.ArgumentNullException: Value cannot be null.
Parameter name: value
at System.String.IndexOf(String value, Int32 startIndex, Int32 count, StringComparison comparisonType)