Warning (2): Use of undefined constant DEFAULT_IMAGE_PATH - assumed 'DEFAULT_IMAGE_PATH' (this will throw an Error in a future version of PHP) [CORE/src/View/HelperRegistry.php, line 153]
Warning (512): Unable to emit headers. Headers sent in file=/var/www/html/vendor/cakephp/cakephp/src/Error/Debugger.php line=971 [CORE/src/Http/ResponseEmitter.php, line 71]
Warning (2): Cannot modify header information - headers already sent by (output started at /var/www/html/vendor/cakephp/cakephp/src/Error/Debugger.php:971) [CORE/src/Http/ResponseEmitter.php, line 168]
Warning (2): Cannot modify header information - headers already sent by (output started at /var/www/html/vendor/cakephp/cakephp/src/Error/Debugger.php:971) [CORE/src/Http/ResponseEmitter.php, line 201]
Error: Connection to Mysql could not be established: SQLSTATE[HY000] [1045] Access denied for user 'demo_crm_ec2'@'172.31.29.44' (using password: YES)

Connection to Mysql could not be established: SQLSTATE[HY000] [1045] Access denied for user 'demo_crm_ec2'@'172.31.29.44' (using password: YES) 📋

Cake\Database\Exception\MissingConnectionException
Toggle Vendor Stack Frames
CORE/src/Database/Driver.php Toggle Arguments
        $retry = new CommandRetry(new ErrorCodeWaitStrategy(static::RETRY_ERROR_CODES, 5), 4);
        try {
            $retry->run($action);
        } catch (PDOException $e) {
            throw new MissingConnectionException(
                [
                    'driver' => App::shortName(static::class, 'Database/Driver'),
                    'reason' => $e->getMessage(),
                ],

If you want to customize this error message, create templates/Error/error500.php