带有端口25的Wordpress WP-Mail SMTP

Question

我无法使用端口25的SMTP帐户发送电子邮件。我具有以下配置：

• SMTP主机：mail.mycompany.ch
• 加密：无
• 端口：25
• 自动TLS：关闭
• 增强：开启
• 用户名：x@mycompany.ch
• 通过：*******

当我尝试发送测试电子邮件时，错误日志文件向我显示：

Versions:
WordPress: 4.9.10
WordPress MS: No
PHP: 7.0.33-0ubuntu0.16.04.2
WP Mail SMTP: 1.4.1

Params:
Mailer: smtp
Constants: Yes
ErrorInfo: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
Host: mail.mycompany.ch
Port: 25
SMTPSecure: string(0) ""
SMTPAutoTLS: bool(false)
SMTPAuth: bool(true)

Server:
OpenSSL: OpenSSL 1.0.2g 1 Mar 2016
Apache.mod_security: No
SMTP Debug:
2019-03-18 13:59:45 Connection: opening to mail.mycompany.ch:25, timeout=300, options=array (
)
2019-03-18 14:01:56 Connection: Failed to connect to server. Error number 2. "Error notice: stream_socket_client(): unable to connect to mail.mycompany.ch:25 (Connection timed out)
2019-03-18 14:01:56 SMTP ERROR: Failed to connect to server: Connection timed out (110)
2019-03-18 14:01:56 SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

谁能帮助我？