When trying to connect to a local SQL server (MAMP) I'm getting this exception:
Exception thrown: 'System.Data.SqlClient.SqlException' in System.Data.dll System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) ---> System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, DbConnectionPool pool, String accessToken, Boolean applyTransientFaultHandling, SqlAuthenticationProviderManager sqlAuthProviderManager) at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource 1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) 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.ProviderBase.DbConnectionClosed.TryOpenConnection(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 login_page.DatabaseClass.dbRead(String sqlQuery) in C:\Users******\DatabaseClass.cs:line 35 ClientConnectionId:00000000-0000-0000-0000-000000000000 Error Number:2,State:0,Class:20

This is the class I'm using to perform a SELECT SQL function

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace login_page
{
    class DatabaseClass
    {
        public void dbSignIn(String username, String password)
        {
            dbRead("SELECT * FROM user_credentials WHERE username = '" + username + "' AND password = '" + password + "'");
        }

        public void dbRegisterUser()
        {
            dbRead("SQL READ TO DATABASE");
            //dbWrite("SQL WRITE TO DATABASE")
        }

        private void dbRead(String sqlQuery)
        {
            SqlDataReader dataReader;
            SqlCommand command;

            // *** CONNECT TO DATABASE
            Console.WriteLine("** Database Connection: Connecting to database");

            SqlConnection dbConnection = new SqlConnection("User Id=root;" + "Password=root;" + "Server=localhost;" + "Trusted_Connection=true;" + "Database=dbmentum;" + "Connection Timeout=10;");
            try
            {
                dbConnection.Open();
                Console.WriteLine("** Database Connection: Connected to database server");

                // *** READ FROM DATABASE
                command = new SqlCommand(sqlQuery, dbConnection);
                dataReader = command.ExecuteReader();

                while (dataReader.Read())
                {
                    Console.WriteLine(dataReader[0].ToString());    
                    Console.WriteLine(dataReader[1].ToString());
                }

                dataReader.Close();
                command.Dispose();
                dbConnection.Close();
            }
            catch (SqlException e)
            {
                Console.WriteLine(e.ToString());
                MessageBox.Show(e.Message, "Mentum - Database Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            /*
            // CLOSE DATABASE
            try
            {
                dbConnection.Close();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            } */
        }
    }
}

All appropriate ports are enabled and database details are correct.