Entity Framework exception "Source provider abandoned Open"

Question

I created a Windows service that listens on a TCP / IP port and stores the received data in a database using the Entity Framework. Most of the time it works fine, but for some time it throws an exception. "The primary provider does not work when opened." to save data in a database. Here are my exception details:

    Exception: 2/27/2014 10:31 AM:
    The underlying provider failed on Open.
     at System.Data.Entity.Core.EntityClient.EntityConnection.Open()
     at System.Data.Entity.Core.Objects.ObjectContext.EnsureConnection()
     at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
     at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClassb.<GetResults>b__9()
     at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)
     at System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
    at System.Data.Entity.Core.Objects.ObjectQuery`1.<System.Collections.Generic.IEnumerable<T>.GetEnumerator>b__0()
     at System.Lazy`1.CreateValue()
     at System.Lazy`1.LazyInitValue()
     at System.Lazy`1.get_Value()
     at System.Data.Entity.Internal.LazyEnumerator`1.MoveNext()
     at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source)
     at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.<GetElementFunction>b__1[TResult](IEnumerable`1 sequence)
     at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.ExecuteSingle[TResult](IEnumerable`1 query, Expression queryRoot)
     at System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.System.Linq.IQueryProvider.Execute[TResult](Expression expression)
    at System.Data.Entity.Internal.Linq.DbQueryProvider.Execute[TResult](Expression expression)
    at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
    at Service.DemoService.Save(String received, TcpClient client)

What is the cause of this exception and how to solve it?

Answer 1

Entity Framework , MultipleActiveResultSets true .

<add name="conn" 
  connectionString="
    Data Source=.\;
    Initial Catalog=TDB;
    UID=admin123;
    PWD=123;
    MultipleActiveResultSets=True"
  providerName="System.Data.SqlClient" />

, .

Answer 2

, SQL Server . , "" , SQL Server .