Hi.

We're trying to set up a new public access section on one of our sites but as soon as you've selected either role based or single user protection and clicked select the dialog box 500s. The logs have the below errors.

    2020-02-25 12:23:02,165 [P3744/D2/T90] ERROR Umbraco.Core.UmbracoApplicationBase - An unhandled exception occurred
System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at umbraco.presentation.umbraco.dialogs.protectPage.selectMode(Object sender, EventArgs e)
   at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
   at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.HandleError(Exception e)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest()
   at System.Web.UI.Page.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
 2020-02-25 12:23:37,422 [P3744/D2/T93] INFO  Umbraco.Web.Mvc.UmbracoPageResult - Executing Umbraco RouteDefinition controller
 2020-02-25 12:23:37,438 [P3744/D2/T93] INFO  Umbraco.Web.Mvc.UmbracoPageResult - Finished (took 6ms)
 2020-02-25 12:23:56,268 [P3744/D2/T30] INFO  Umbraco.Forms.Web.Services.RecordService - Form Entry Submitted - Form Entry Id: '0', Form Id: '7b4628a1-1267-43b1-b734-45dd0610f764', User: ''
 2020-02-25 12:23:57,001 [P3744/D2/T30] INFO  Umbraco.Forms.Web.Services.RecordService - Form Entry Approved - Form Entry Id: '5045', Form Id: '7b4628a1-1267-43b1-b734-45dd0610f764', User: ''
 2020-02-25 12:24:25,799 [P3744/D2/T81] INFO  Umbraco.Web.Mvc.UmbracoPageResult - Executing Umbraco RouteDefinition controller
 2020-02-25 12:24:25,799 [P3744/D2/T81] INFO  Umbraco.Web.Mvc.UmbracoPageResult - Finished (took 5ms)
 2020-02-25 12:25:44,909 [P3744/D2/T91] INFO  Umbraco.Web.Mvc.UmbracoPageResult - Executing Umbraco RouteDefinition controller
 2020-02-25 12:25:45,112 [P3744/D2/T91] INFO  Umbraco.Web.Mvc.UmbracoPageResult - Finished (took 208ms)
 2020-02-25 12:26:35,861 [P3744/D2/T72] INFO  Umbraco.Web.Mvc.UmbracoPageResult - Executing Umbraco RouteDefinition controller
 2020-02-25 12:26:36,063 [P3744/D2/T72] INFO  Umbraco.Web.Mvc.UmbracoPageResult - Finished (took 204ms)
 2020-02-25 12:26:45,049 [P3744/D2/T85] ERROR Umbraco.Core.UmbracoApplicationBase - An unhandled exception occurred
System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at umbraco.presentation.umbraco.dialogs.protectPage.selectMode(Object sender, EventArgs e)
   at System.Web.UI.WebControls.Button.OnClick(EventArgs e)
   at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.HandleError(Exception e)
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
   at System.Web.UI.Page.ProcessRequest()
   at System.Web.UI.Page.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

We have 2 other public access areas on the same site and they're working fine, we just don't seem to be able to set up and more.

We've tried the same thing on our dev environment which is only about 4 weeks out of sync database wise and it works fine so it looks like there may be an issue with our live environment. We're currently running v7.15.2 across all environments.

Has anyone got any ideas?

Cheers

Chris