I'm getting the following error in Sitecore 10.1 when Installing Unicorn

Unknown connection string. Name: '$(1)'

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.InvalidOperationException: Unknown connection string. Name: '$(1)'

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

[InvalidOperationException: Unknown connection string. Name: '$(1)']
   Sitecore.Configuration.DefaultSettings.GetConnectionString(String connectionStringName) +384
   Sitecore.Configuration.DefaultFactory.CreateFromConnectionStringName(XmlNode configNode, String[] parameters, Boolean assert) +182
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper) +188
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert) +72
   Sitecore.Configuration.DefaultFactory.GetConstructorParameters(XmlNode configNode, String[] parameters, Boolean assert) +161
   Sitecore.Configuration.DefaultFactory.CreateFromTypeName(XmlNode configNode, String[] parameters, Boolean assert) +114
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper) +163
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert) +72
   Sitecore.Configuration.DefaultFactory.CreateObject(String configPath, String[] parameters, Boolean assert) +703
   Sitecore.Configuration.DefaultFactory.CreateFromReference(XmlNode configNode, String[] parameters, Boolean assert) +170
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper) +116
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert) +72
   Sitecore.Configuration.DefaultFactory.GetInnerObject(XmlNode paramNode, String[] parameters, Boolean assert) +842
   Sitecore.Configuration.DefaultFactory.AssignProperties(XmlNode configNode, String[] parameters, Object obj, Boolean assert, Boolean deferred, IFactoryHelper helper) +545
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper) +326
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert) +72
   Sitecore.Configuration.DefaultFactory.CreateObject(String configPath, String[] parameters, Boolean assert) +703
   Sitecore.Configuration.DefaultFactory.GetDatabase(String name, Boolean assert) +157
   Sitecore.Configuration.DefaultFactory.GetDatabase(String name) +55
   Sitecore.Configuration.DefaultFactory.GetDatabases() +121
   Sitecore.Data.SqlServer.SqlServerLinkDataProviderFactory.CreateProvidersForAllDatabases() +161

[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) +269
   System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +146
   Sitecore.Reflection.ReflectionUtil.CallStaticMethod(String typeName, String methodName, Object[] parameters) +165
   Sitecore.Configuration.DefaultFactory.CreateFromFactoryMethod(XmlNode configNode, String[] parameters, Boolean assert) +534
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper) +91
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert) +72
   Sitecore.Configuration.DefaultFactory.GetConstructorParameters(XmlNode configNode, String[] parameters, Boolean assert) +161
   Sitecore.Configuration.DefaultFactory.CreateFromTypeName(XmlNode configNode, String[] parameters, Boolean assert) +114
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper) +163
   Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert) +72
   Sitecore.Configuration.DefaultFactory.CreateObject(String configPath, String[] parameters, Boolean assert) +703
   Sitecore.Configuration.DefaultFactory.GetLinkDatabase() +36
   Sitecore.DefaultGlobals.Load() +294
   (Object , Object ) +55
   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
   Sitecore.Nexus.Web.HttpModule.Application_Start() +146
   Sitecore.Nexus.Web.HttpModule.Init(HttpApplication app) +898
   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) +724