Error trying to run ASE sql (sybase) on .net core web api "A request to send or receive data was disallowed ..."

Question

When I run this SQL, I get this error

This is the second SQL I run, but I tried running the 1st SQL that works twice and a row and it worked fine, so maybe not a open connection issue?

A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using a send to call) no address was supplied.

last time I got that error, in very similar code, it was because I left the "@" off the variable name in the args section.

So I strongly suspect this is the bad generic error for "Your SQL calling code is messed up somehow" or "that returned 0 rows"(man, I hope its not the latter)

public List<EnrTypeSepInfoCV> GetEnrTypeSepInfo(long enrId)
{
    var aseSqlConnectionString = configuration.GetConnectionString("SybaseDBDapper");

    string sql = "";

    sql += "select et.enrtype_id, ";
    sql += " et.active as stud_status, ";
    sql += " s.sep_dt ";
    sql += "from enrollment_type et,separation s ";
    sql += "where et.enrtype_id *= s.enrtype_id ";
    sql += "and et.enr_id = @al_enr_id  ";

    dapperTools.DapperCustomMapping<EnrTypeSepInfoCV>();

    try
    {
        using (IDbConnection db = new AseConnection(aseSqlConnectionString))
        {
            var arguments = new
            {
                @al_enr_id = enrId
            };

            List<EnrTypeSepInfoCV> ll = new List<EnrTypeSepInfoCV>();

            ll = db.Query<EnrTypeSepInfoCV>(sql, arguments).ToList();
            return ll;
        }
    }
    catch (Exception ex)
    {
        Trace.WriteLine(ex.ToString());
        return null;
    }
}

If I pull the SQL out, replace the variable with the passed in value everything works.

I looked line by line comparing this to a working SQL call method and I can't see any differences. Anyone know what I did wrong?

Is there a way to get more informative errors in situations like this?

If it matters, I'm writing a .Net Core web API Service to be consumed by a Vue app running against a Sybase DB v12.*.

I have other API methods working correctly, that call the DB the same way.

Here is my data object

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace SpProofOfConceptAPI.Dto
{

    public class EnrTypeSepInfoCV
    {
        [Dapper.Column("enrtype_id")]
        public Int64 EnrTypeId { get; set; }

        [Dapper.Column("stud_status")]
        public string StudStatus { get; set; }

        [Dapper.Column("sep_dt")]
        public DateTime? SepDt { get; set; }
    }
}

Answer 1

Okay,

So this message appears to be a generic "something went wrong connecting" message.

In my case, it was the connection timeout expiring. the Default is 15s, I changed it to 600s, and it's working fine. (We have some long running reports that can take a long time)

Since it's on ASE, I just added 'Connection Timeout = 600;'.