D365 FO - Ошибка A network-related or instance-specific error occurred while establishing a connection to SQL Server

[belugin]

Вот пример связи таблиц на C# - reference связывает names

            var interestingTypes = new[] { "Classes", "Tables" };
            var xrefDb = new XrefDBDataContext(connectionString);
            var coreReferences =
                from reference in xrefDb.References
                join targetName in xrefDb.Names on
                    reference.TargetId equals targetName.Id
                join targetModule in xrefDb.Modules on
                    targetName.ModuleId equals targetModule.Id
                join sourceName in xrefDb.Names on
                    reference.SourceId equals sourceName.Id
                join sourceModule in xrefDb.Modules on
                    sourceName.ModuleId equals sourceModule.Id
                where
                (
                    targetModule.Name == "ElectronicReporting" ||
                    targetModule.Name == "ElectronicReportingCore" ||
                    targetModule.Name == "ElectronicReportingMapping" ||
                    targetModule.Name == "ElectronicReportingForAx" ||
                    targetModule.Name == "TaxEngine"
                    ) 
                    && 
                    reference.Kind == CrossReferenceKind.ClassExtended
                select new
                {
                    Reference = reference,
                    TargetName = targetName,
                    TargetModule = targetModule,
                    SourceName = sourceName,
                    SourceModule = sourceModule
                };