将Discourse连接到postalserver.io以实现SMTP

嘿,我正尝试将 Discourse 连接到自托管的 postalserver.io SMTP 服务器。我收到了来自 Discourse 的以下错误:

Jobs::HandledExceptionWrapper: Wrapped OpenSSL::SSL::SSLError: SSL_connect SYSCALL returned=5 errno=0 peeraddr=x.x.x.x:25 state=SSLv3/TLS write client hello

DISCOURSE_SMTP_ADDRESS: <address>
DISCOURSE_SMTP_PORT: 25
DISCOURSE_SMTP_USER_NAME: <username>
DISCOURSE_SMTP_PASSWORD: "<password>"
DISCOURSE_SMTP_ENABLE_START_TLS: true           # (optional, default true)
DISCOURSE_SMTP_DOMAIN: <domain>
DISCOURSE_NOTIFICATION_EMAIL: <no-reply>
DISCOURSE_SMTP_AUTHENTICATION: "plain"
DISCOURSE_SMTP_OPENSSL_VERIFY_MODE: none