System.ArgumentException: Value cannot be null or empty. (Parameter 'url') at Microsoft.AspNetCore.Mvc.RazorPages.PageModel.RedirectPreserveMethod(String url) at SkolaIn.IndexModel.OnGet(String strankaurl, String podstrankaurl, String urlstring, String temp) at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.ExecutorFactory.GenericTaskHandlerMethod.Convert[T](Object taskAsObject) at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.ExecutorFactory.GenericTaskHandlerMethod.Execute(Object receiver, Object[] arguments) at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionInvoker.InvokeHandlerMethodAsync() at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionInvoker.InvokeNextPageFilterAsync() at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionInvoker.Rethrow(PageHandlerExecutedContext context) at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionInvoker.InvokeInnerFilterAsync() at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|24_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync() --- End of stack trace from previous location where exception was thrown --- at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope) at Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger) at Microsoft.AspNetCore.Diagnostics.StatusCodePagesMiddleware.Invoke(HttpContext context) at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context) HEADERS ======= Accept: */* Connection: close Host: jidelna.stefcova.cz User-Agent: claudebot