C# SignalR - Fix Multiple Connection String Issue

I have this class from where i am getting data from store procedure public class StatisticalRepository { string connectionString; private readonly StatisticalDBContext dbContext; public StatisticalRepository(string connectionString, StatisticalDBContext _dbContext) { [login to view URL] = connectionString; [login to view URL] = _dbContext; } public async Task<List<StatsData>> GetStatsData() { try { string sqlTextList = $"EXECUTE GetStatsData"; List<StatsData> response = await [login to view URL](sqlTextList).ToListAsync(); // Reload the entities from the StatsDatas table foreach (var emp in response) { [login to view URL](emp).Reload(); } return response; } catch (Exception ex) { throw; } } } also from subscriberhub below code SqlTableDependency<StatsData> tableDependency; TrueHub trueHub; public SubscribeStatsTableDependency(TrueHub trueHub) { [login to view URL] = trueHub; } public void SubscribeTableDependency(string connectionString) { tableDependency = new SqlTableDependency<StatsData>(connectionString); [login to view URL] += TableDependency_OnChanged; [login to view URL] += TableDependency_OnError; [login to view URL](); } i am getting issue error "'A second operation was started on this context instance before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext" you need to fix issue on localhost currently after we get rid of this we can deploy on server.