Cannot send any email SMTP / PHP Email

aaP_mhoang8595

1/ I use a dynamic IPs
2/ I use cloudflare to config website using CNAME
3/ I cannot send any email in my server

--- WP
`Versions:
WordPress: 6.7.1
WordPress MS: No
PHP: 8.3.15
WP Mail SMTP: 4.3.0

Params:
Mailer: smtp
Constants: No
ErrorInfo: SMTP Error: Could not connect to SMTP host. Failed to connect to serverSMTP server error: Failed to connect to server
Host: smtp.larksuite.com
Port: 465
SMTPSecure: ssl
SMTPAutoTLS: bool(true)
SMTPAuth: bool(true)

Server:
OpenSSL: OpenSSL 1.1.1o 3 May 2022

Debug:
Email Source: WP Mail SMTP
Mailer: Other SMTP
SMTP Error: Could not connect to SMTP host. Failed to connect to serverSMTP server error: Failed to connect to server

SMTP Debug:
2025-01-22 02:53:10 Connection: opening to ssl://smtp.larksuite.com:465, timeout=30, options=array()

2025-01-22 02:53:21 Connection failed. Error #2: stream_socket_client(): SSL operation failed with code 1. OpenSSL Error messages:error:1408F10B:SSL routines:ssl3_get_record:wrong version number [/www/wwwroot/toho.vn/wp-includes/PHPMailer/SMTP.php line 412]

2025-01-22 02:53:21 Connection failed. Error #2: stream_socket_client(): Failed to enable crypto [/www/wwwroot/toho.vn/wp-includes/PHPMailer/SMTP.php line 412]

2025-01-22 02:53:21 Connection failed. Error #2: stream_socket_client(): Unable to connect to ssl://smtp.larksuite.com:465 (Unknown error) [/www/wwwroot/toho.vn/wp-includes/PHPMailer/SMTP.php line 412]

2025-01-22 02:53:21 SMTP ERROR: Failed to connect to server: (0)

SMTP Error: Could not connect to SMTP host. Failed to connect to server`

-- Dolibarr

aaPanel_Kern

Hello, is this the A record of your MX record? It can be viewed in the DNS records of the domain name. If it is not recommended that you use pan-domain SSL, you can refer to the following tutorial.
https://www.aapanel.com/docs/Function/Tutorial/Mail_SMTP_configuration.html

aaP_mhoang8595

Currently, I use SMTP from larksuite.

My domain is dynamic config in cloudflare

aaP_mhoang8595

Yesterday I config the email server -> it works sent but no receive by client. Hmmmm.

aaPanel_Kern

Hello, please check the A record pointed to by the MX record, whether the A record points to the IP of the server, and the proxy cannot be used.
Also check if the mail server's SSL certificate contains an A record?

aaP_mhoang8595

I just turn this one off? you mean this proxy right

aaPanel_Kern

please check the A record pointed to by the MX record, whether the A record points to the IP of the server,
aaP_mhoang8595

aaP_mhoang8595

I sent mail via this is ok send and receive this is SMTP like gmail provided by Lark.

But the problem is ALL SMTP not working. Not just that

aaPanel_Kern

Hello, please check whether the SSL certificate of the mail server is correct?
If the SSL certificate does not contain an A record, encrypted ports such as 465 and 587 cannot be used normally.
You can refer to this tutorial to configure a pan-domain SSL certificate.
https://www.aapanel.com/docs/Function/Tutorial/Mail_SMTP_configuration.html

At the same time, check the postfix configuration, which can be viewed in the server status
"mail.135mailtest.com" is replaced with your domain name
Put:
smtpd_tls_chain_files=/etc/ssl/private/ssl-cert-snakeoil.key,/etc/ssl/certs/ssl-cert-snakeoil.pem
Change to:
smtpd_tls_chain_files = /www/server/panel/plugin/mail_sys/cert/135mailtest.com/privkey.pem,/www/server/panel/plugin/mail_sys/cert/135mailtest.com/fullchain.pem
Note to replace 135mailtest.com with your domain name.
Also check /www/server/panel/plugin/mail_sys/cert/135mailtest.com/ for privkey.pem and fullchain.pem files

You can use this command to check whether the correct SSL is configured
openssl s_client -connect mail.135mailtest.com:587 -starttls smtp
or
openssl s_client -connect mail.135mailtest.com:465

If the display is not OK, try to save the SSL certificate again, or please re-apply for SSL

aaP_mhoang8595

aaPanel_Kern

Currently,

After long day config still not working but we have some result:

1/ Can receive email from another
2/ Can send internal to internal as long as it have same domain I can send it

Problem -----
3/ Cannot send to another yet!

aaP_mhoang8595

How to view server status?

aaP_mhoang8595

Debug:
Email Source: WP Mail SMTP
Mailer: Other SMTP
SMTP Error: Could not connect to SMTP host. Failed to connect to serverSMTP server error: Failed to connect to server

SMTP Debug:
2025-01-22 11:37:01 Connection: opening to smtp.gmail.com:587, timeout=30, options=array()

2025-01-22 11:37:01 Connection: opened

2025-01-22 11:37:01 SERVER -> CLIENT: 220 mail.toho.vn ESMTP Postfix (Ubuntu)

2025-01-22 11:37:01 CLIENT -> SERVER: EHLO toho.vn

2025-01-22 11:37:01 SERVER -> CLIENT: 250-mail.toho.vn250-PIPELINING250-SIZE 102400000250-VRFY250-ETRN250-STARTTLS250-ENHANCEDSTATUSCODES250-8BITMIME250-DSN250-SMTPUTF8250 CHUNKING

2025-01-22 11:37:01 CLIENT -> SERVER: STARTTLS

2025-01-22 11:37:01 SERVER -> CLIENT: 220 2.0.0 Ready to start TLS

2025-01-22 11:37:01 Connection failed. Error #2: stream_socket_enable_crypto(): Peer certificate CN=toho.vn' did not match expected CN=smtp.gmail.com' [/www/wwwroot/toho.vn/wp-includes/PHPMailer/SMTP.php line 495]

SMTP Error: Could not connect to SMTP host. Connection failed. stream_socket_enable_crypto(): Peer certificate CN=toho.vn' did not match expected CN=smtp.gmail.com'

2025-01-22 11:37:01 CLIENT -> SERVER: QUIT

2025-01-22 11:37:01

2025-01-22 11:37:01 Connection: closed

SMTP Error: Could not connect to SMTP host. Connection failed. stream_socket_enable_crypto(): Peer certificate CN=toho.vn' did not match expected CN=smtp.gmail.com'

aaP_mhoang8595

I can receive the email but not send SMTP?