I was creating a web api in ASP.NET MVC but it show error format of the initialization string does not conform to specification starting at index 1.

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<Error>
<Message>An error has occurred.</Message>
<ExceptionMessage>
Format of the initialization string does not conform to specification starting at index 1.
</ExceptionMessage>
<ExceptionType>System.ArgumentException</ExceptionType>
<StackTrace>
at System.Data.Entity.Core.EntityClient.Internal.DbConnectionOptions.GetKeyValuePair(String connectionString, Int32 currentPosition, StringBuilder buffer, String& keyname, String& keyvalue) at System.Data.Entity.Core.EntityClient.Internal.DbConnectionOptions.ParseInternal(IDictionary`2 parsetable, String connectionString, IList`1 validKeywords) at System.Data.Entity.Core.EntityClient.Internal.DbConnectionOptions..ctor(String connectionString, IList`1 validKeywords) at System.Data.Entity.Core.EntityClient.EntityConnection.ChangeConnectionString(String newConnectionString) at System.Data.Entity.Core.EntityClient.EntityConnection..ctor(String connectionString) at System.Data.Entity.Internal.LazyInternalConnection.InitializeFromConnectionStringSetting(ConnectionStringSettings appConfigConnection) at System.Data.Entity.Internal.LazyInternalConnection.TryInitializeFromAppConfig(String name, AppConfig config) at System.Data.Entity.Internal.LazyInternalConnection.Initialize() at System.Data.Entity.Internal.LazyInternalConnection.get_ProviderName() at System.Data.Entity.Internal.LazyInternalContext.get_ProviderName() at System.Data.Entity.Internal.DefaultModelCacheKeyFactory.Create(DbContext context) at System.Data.Entity.Internal.LazyInternalContext.InitializeContext() at System.Data.Entity.Internal.InternalContext.Initialize() at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType) at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize() at System.Data.Entity.Internal.Linq.InternalSet`1.GetEnumerator() at System.Data.Entity.Infrastructure.DbQuery`1.System.Collections.Generic.IEnumerable<TResult>.GetEnumerator() at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection) at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source) at Part4_CreateDataAndSqlServer.Controllers.EmployeesController.Get() in E:\Visual Studio 2019\WebApi\Web_API\Part4_CreateDataAndSqlServer\Part4_CreateDataAndSqlServer\Controllers\EmployeesController.cs:line 17 at lambda_method(Closure , Object , Object[] ) at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass6_2.<GetExecutor>b__2(Object instance, Object[] methodParameters) at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments) at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancellationToken) --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__1.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__5.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__15.MoveNext()
</StackTrace>
</Error>

public class EmployeesController : ApiController
    {
        public IEnumerable<emp> Get()
        {
            using (EmployeeWebAPI empObj = new EmployeeWebAPI())
            {
                return empObj.emps.ToList();
            }
        }
        public emp Get(int Id)
        {
            using (EmployeeWebAPI empObj = new EmployeeWebAPI())
            {
                return empObj.emps.FirstOrDefault(e => e.Id == Id);
            }
        }
    }