Using Sitecore 10.1.2

In my local machine, I have installed the instance and deployed the code and Sitecore items. The solution uses TDS.

This is a multi-site project and one of the Site Grouping items is like this:

----field----
field: {475031D8-724D-463C-80B2-90839DD1AD98}
name: VirtualFolder
key: virtualfolder
content-length: 1

Meaning, there is no field value, but still the content-length is 1.
Could this be a reason. But isn't this a content item. Will the CMS still not load because of this? Even the login page isn't loading.

Anyways, I added / as the field value in the code for that item and then tried to do TDS Sync with Sitecore. But it throws an error saying:

That's because the CMS isn't loading.

Wen I browse my CMS, it throws this error:

The path must start with a '/' followed by one or more characters. Parameter name: value
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentException: The path must start with a '/' followed by one or more characters. Parameter name: value

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[ArgumentException: The path must start with a '/' followed by one or more characters. Parameter name: value]
Microsoft.Owin.PathString..ctor(String value) +119
Owin.MapExtensions.Map(IAppBuilder app, String pathMatch, Action`1 configuration) +108
Sitecore.Owin.Authentication.IdentityServer.Pipelines.Initialize.LogoutEndpoint.Process(InitializeArgs args) +244 (Object , Object ) +14
Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args) +490
Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain, Boolean failIfNotExists) +236 Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, String pipelineDomain) +22

[TargetInvocationException: Exception has been thrown by the target of an invocation.] System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) +0
System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) +216
System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +182 Owin.Loader.<>c__DisplayClass19_1.b__0(IAppBuilder builder) +93
Owin.Loader.<>c__DisplayClass9_0.b__0(IAppBuilder builder) +224
Microsoft.Owin.Host.SystemWeb.OwinAppContext.Initialize(Action1 startup) +897 Microsoft.Owin.Host.SystemWeb.OwinBuilder.Build(Action1 startup) +51 Microsoft.Owin.Host.SystemWeb.OwinHttpModule.InitializeBlueprint() +101 System.Threading.LazyInitializer.EnsureInitializedCore(T& target, Boolean& initialized, Object& syncLock, Func`1 valueFactory) +139 Microsoft.Owin.Host.SystemWeb.OwinHttpModule.Init(HttpApplication context) +160
System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +584
System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +168
System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +277
System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +369

[HttpException (0x80004005): Exception has been thrown by the target of an invocation.]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +532
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +111 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +719