I decided to install a version on SI on my hosted account with byethost and originally I had the exact same problem.
They advised me to use port 384 instead of 290 and success it worked!!!
Only problem is that using the same port on my locally hosted is still not working. But I get a different error this time in php.log. I have replaced the name of the hostname and its ip in the log.
[04-Oct-2019 04:01:34 America/Los_Angeles] PHP Fatal error: Uncaught Swift_TransportException: Expected response code 354 but got code "503", with message "503-All RCPT commands were rejected with this error:^M 503-Please turn on SMTP Authentication in your mail client. <hostname>^M 503-(invoices.master2019.org) [<my IP>]:60170 is not permitted to relay^M 503-through this server without authentication.^M 503 Valid RCPT command must precede DATA^M " in /var/www/simpleinvoices/simpleinvoices-master_2019.2/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php:457 Stack trace: #0 /var/www/simpleinvoices/simpleinvoices-master_2019.2/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(341): Swift_Transport_AbstractSmtpTransport->assertResponseCode('503-All RCPT co...', Array) #1 /var/www/simpleinvoices/simpleinvoices-master_2019.2/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/EsmtpTransport.php(305): Swift_Transport_AbstractSmtpTransport->executeCommand('DATA\r\n', Array, Array, false, N in /var/www/simpleinvoices/simpleinvoices-master_2019.2/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php on line 457