ADO.Net code is working at Console application. But not working on WEB API project. Database is at AWS

I am working on WEB API. when i am trying to insert data using ADO.NET or Entity Framework. It shows an Error Message "Attempted to access an unloaded appdomain. (Exception from HRESULT: 0x80131014)". but the same code is working on Console Application project.Database Server is at AWS. Code are as below.

    SqlConnection con = new SqlConnection(constring);
    con.open();
    sqlcommand cmd = new sqlcommand();
    cmd.Connection = con;
    cmd.commandtext = "uspsaveregistration";
    cmd.commandtype = commandtype.storedprocedure;
    sqlparameter[] sqlp = new sqlparameter[] {
        new sqlparameter("@mobile_no",sqldbtype.varchar),
        new sqlparameter("@password",sqldbtype.varchar),
        new sqlparameter("@first_name",sqldbtype.varchar),
        new sqlparameter("@last_name",sqldbtype.varchar),
        new sqlparameter("@gender",sqldbtype.varchar),
        new sqlparameter("@dob",sqldbtype.varchar),
        new sqlparameter("@designation",sqldbtype.varchar),
        new sqlparameter("@address",sqldbtype.varchar),
        new sqlparameter("@mapid",sqldbtype.int),
        new sqlparameter("@createormodified",sqldbtype.bit),
        new sqlparameter("@email",sqldbtype.varchar),
        new sqlparameter("@mpin",sqldbtype.varchar),
        new sqlparameter("@lga_id",sqldbtype.int),
        new sqlparameter("@entityid",sqldbtype.varchar),
        new sqlparameter("@nownowid",sqldbtype.varchar),
        new sqlparameter("@type_code",sqldbtype.int),
        new sqlparameter("@beat_code",sqldbtype.varchar),
        new sqlparameter("@modify_by",sqldbtype.varchar),
        new sqlparameter("@synccount",sqldbtype.int),
        new sqlparameter("@isonline",sqldbtype.bit)
    };
    sqlp[0].value = mobileno;
    sqlp[1].value = password;
    sqlp[2].value = firstname;
    sqlp[3].value = lastname;
    sqlp[4].value = gender;
    sqlp[5].value = dob;
    sqlp[6].value = designation;
    sqlp[7].value = address;
    sqlp[8].value = mapid;
    sqlp[9].value = createormodi;
    sqlp[10].value = email;
    sqlp[11].value = mpin;
    sqlp[12].value = lgaid;
    sqlp[13].value = entityid;
    sqlp[14].value = nownowid;
    sqlp[15].value = typecode;
    sqlp[16].value = beatcode;
    sqlp[17].value = modifyby;
    sqlp[18].value = syncount;
    sqlp[19].value = isonline;
    foreach (sqlparameter para in sqlp)
    {
        cmd.parameters.add(para);
    }
    cmd.executenonquery();
    con.close();