An error occurred while attaching module (Dynamicweb.Frontend.Content)

System.InvalidOperationException: Timeout expired.  The timeout period elapsed prior to obtaining a connection from the pool.  This may have occurred because all pooled connections were in use and max pool size was reached.
   at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)
   at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
   at System.Data.SqlClient.SqlConnection.Open()
   at Dynamicweb.Data.DatabaseConnectionProvider.CreateConnection(Boolean open)
   at Dynamicweb.Data.Database.CreateConnection()
   at DanskRideForbund.BusinessLayer.Provider.DataProvider.GetCollection[T](SqlCommand command, SqlConnection connection) in D:\a\1\s\DanskRideForbund.BusinessLayer\Provider\DataProvider.cs:line 41
   at DanskRideForbund.DataAccessLayer.RiderData.GetRidersById(ICollection`1 riderIds) in D:\a\1\s\DanskRideForbund.DataAccessLayer\RiderData.cs:line 106
   at DanskRideForbund.BusinessLayer.Provider.RiderProvider.GetRiderById(String riderId) in D:\a\1\s\DanskRideForbund.BusinessLayer\Provider\RiderProvider.cs:line 333
   at DanskRideForbund.CustomModules.RiderModule.RiderModuleFrontend.ShowRider(RiderHelper helper, DataArea dataArea) in D:\a\1\s\Application\CustomModules\RiderModule\RiderModuleFrontend.cs:line 154
   at DanskRideForbund.CustomModules.RiderModule.RiderModuleFrontend.GetContent() in D:\a\1\s\Application\CustomModules\RiderModule\RiderModuleFrontend.cs:line 49
   at Dynamicweb.Frontend.Content.GetModuleOutput(Paragraph paragraph, PageView pageview)