Update: 
 

Exception on 2025-04-15T17:42:00.0432498Z. CorrelationId: 04b9369d-fb28-4bbe-a2dc-6f0b65696ad4
Addtional: Message: SmartObject property DisplayName is a required property for selected method List. Value must be set..
Exception:
System.NullReferenceException: SmartObject property DisplayName is a required property for selected method List. Value must be set.
   at SourceCode.SmartObjects.Client.SmartObject.Validate(Boolean isList)
   at SourceCode.SmartObjects.Client.SmartObjectClientServer.GetSmartObjectReader(SmartObject smartObject, ExecuteListReaderOptions options, Dictionary`2& propertyReference)
   at SourceCode.Forms.AppFramework.FormsApiToXml.GetSmartObjectReader(ExecuteListReaderOptions options)
   at SourceCode.Forms.AppFramework.FormsApiToXml.ToListResults(SmartMethodBase executedMethod, Boolean overrideListCount)
   at SourceCode.Forms.AppFramework.FormRuntime.ExecuteListMethod(BrokerSmartObject brokerSmo, SmartObjectBrokerMetaData brokerMetaData, SmartObject sobj, BrokerMethod brokerMethod, SmartMethodBase thisMethod)
   at SourceCode.Forms.AppFramework.FormRuntime.SmartObjectExecution(BrokerSmartObject brokerSmo, SmartObjectBrokerMetaData brokerMetaData)
   at SourceCode.Forms.AppFramework.FormRuntime.WorkXmlToApi(BrokerPackageCollection packages)
   at SourceCode.Forms.AppFramework.FormRuntime.WorkXmlToApi(Stream input, Stream output)
   at SourceCode.Forms.Runtime.AJAXCall.ProcessRequestInternal(HttpContext context)
URL: /Runtime/Runtime/AjaxCall.ashx
QueryString: 
Headers:
    Connection:keep-alive

It looks like one of your SmartObject call with a List method requires the DisplayName input for it to be able to execute successfully.  What type of SmartObject is this?

You may have to check your rules to see if there is a missing input mapping for a required field, or the control that you are mapping to DisplayName is empty.

Once you locate the rule, you can add a show a message action before it and print out the control/field that you are using for the DisplayName input mapping to see if it is truly empty.

This issue was fixed. The anonymous access in the form was being checked and has blocked the values from initializing.