WP Mail SMTP Failed to Send Email

Resolved

(@kentchee)

Hi there,

I have using WP Mail SMTP for many years but recently I noticed it just faile to send emails. 

There are simialr issues in the forum, but once we tested the Openssl on the servers and go the cert chain correct. It is successfuly correctly connected to the recipeint server.

So now I'm puzzeled what else to look into?

Hpe someone can giveme some clues.

The debug log as follow:



Versions:
WordPress: 6.8.2
WordPress MS: No
PHP: 8.1.33
WP Mail SMTP: 4.5.0

Params:
Mailer: smtp
Constants: No
ErrorInfo: SMTP Error: Could not connect to SMTP host. Connection failed. stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages: error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failedSMTP server error: QUIT command failed Detail: t���.�68���C&]@���T��q���Fj4e1����H��H�0��G�?��+G���5��n�O7Uԑ�7ʻ$��?�c�j"�gFv)u����M� X�c��s���R;&WG���5^��Rh*!���j1mur�s�R��~� P��VWP� *� G�s�(q�գ1
Host: mymail2.domain.com.my
Port: 587
SMTPSecure:tls
SMTPAutoTLS:bool(true)
SMTPAuth:bool(true)

Server:
OpenSSL: OpenSSL 1.1.1k FIPS 25 Mar 2021

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 code: 111 Additional SMTP info: Connection refused

SMTP Debug:
2025-07-29 04:07:39 Connection: opening to mymail2.simplenet.com.my:587, timeout=30, options=array()
2025-07-29 04:07:39 Connection: opened
2025-07-29 04:07:39 SERVER -> CLIENT: 220-server2.domain.com ESMTP Exim 4.98.2 #2 Tue, 29 Jul 2025 12:07:39 +0800 220-We do not authorize the use of this system to transport unsolicited, 220 and/or bulk e-mail.
2025-07-29 04:07:39 CLIENT -> SERVER: EHLO www.domain.com
2025-07-29 04:07:39 SERVER -> CLIENT: 250-server2.domain.com Hello www.domain.com [42.0.28.87]250-SIZE 52428800250-LIMITS MAILMAX=1000 RCPTMAX=50000250-8BITMIME250-PIPELINING250-PIPECONNECT250-AUTH PLAIN LOGIN250-STARTTLS250 HELP
2025-07-29 04:07:39 CLIENT -> SERVER: STARTTLS
2025-07-29 04:07:39 SERVER -> CLIENT: 220 TLS go ahead
2025-07-29 04:07:39 Connection failed. Error #2: stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages:error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed [/home/domain/public_html/wp-includes/PHPMailer/SMTP.php line 496]
SMTP Error: Could not connect to SMTP host. Connection failed. stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages:error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed
2025-07-29 04:07:39 CLIENT -> SERVER: QUIT
2025-07-29 04:07:39
2025-07-29 04:07:39
2025-07-29 04:07:39 Connection: closed
SMTP Error: Could not connect to SMTP host. Connection failed. stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages:error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed

Viewing 1 replies (of 1 total)

Plugin Support Darshana
(@darshanaw)

10 months, 3 weeks ago

Hi @kentchee,

Thank you for sharing the error details. It looks like you’re using Let’s Encrypt as your SSL. Since these certificates renew periodically, it’s possible you encountered a temporary issue during a renewal phase.

If you’re still experiencing the issue, I recommend reaching out to your email provider for further assistance, as the error originating from their end.

I also see the following message on your debug log:
We do not authorize the use of this system to transport unsolicited, 220 and/or bulk e-mail.

Please share the full error log with your SMTP provider and they should be able to assist you accordingly.

I hope this helps. Thanks!

Viewing 1 replies (of 1 total)

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