Signal R EF Core DB Context errored out with SQL Table dependency

Hi,

I am displaying SQL DB table column value change in Angular UI using Signal R and EF Core. When there is a value change in database table i am getting below error message. 

System.InvalidOperationException: '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. 

Code snippet: 

await Clients.Clients(this.Context.ConnectionId).SendAsync("marketPriceChangeResponse", marketPrice.ToList());