Test Emails not working

  • Resolved frehbein

    (@frehbein)


    5 months, 4 weeks ago

    Hi,

    My form always worked until a few days ago. I installed your plugin to try and solve this problem, but it’s still not working, and the test email is also failing.

    I tried to change my email’s password, using both SSL and TLS encryption, as well as many other suggestions from your forum.

    I need help fixing this.

    Here is the Error Log

    Versions:
    WordPress: 6.8.3
    WordPress MS: No
    PHP: 7.4.33
    WP Mail SMTP: 4.7.1

    Params:
    Mailer: smtp
    Constants: No
    ErrorInfo: SMTP Error: Could not authenticate.
    Host: smtp.hostinger.com
    Port: 587
    SMTPSecure:    tls
    SMTPAutoTLS:bool(true)
    SMTPAuth:bool(true)

    Server:
    OpenSSL: OpenSSL 1.1.1w 11 Sep 2023
    Apache.mod_security: No

    Debug:
    Email Source: WP Mail SMTP Mailer: Other SMTP SMTP Error: Could not authenticate.

    SMTP Debug:
    2025-11-29 11:54:09 Connection: opening to smtp.hostinger.com:587, timeout=30, options=array()
    2025-11-29 11:54:09 Connection: opened
    2025-11-29 11:54:09 SERVER -> CLIENT: 220 ESMTP smtp.hostinger.com
    2025-11-29 11:54:09 CLIENT -> SERVER: EHLO seguefa.com
    2025-11-29 11:54:09 SERVER -> CLIENT: 250-smtp.hostinger.com250-PIPELINING250-SIZE 48811212250-ETRN250-STARTTLS250-AUTH PLAIN LOGIN250-ENHANCEDSTATUSCODES250-8BITMIME250-DSN250 CHUNKING
    2025-11-29 11:54:09 CLIENT -> SERVER: STARTTLS
    2025-11-29 11:54:09 SERVER -> CLIENT: 220 2.0.0 Ready to start TLS
    2025-11-29 11:54:10 CLIENT -> SERVER: EHLO seguefa.com
    2025-11-29 11:54:10 SERVER -> CLIENT: 250-smtp.hostinger.com250-PIPELINING250-SIZE 48811212250-ETRN250-AUTH PLAIN LOGIN250-ENHANCEDSTATUSCODES250-8BITMIME250-DSN250 CHUNKING
    2025-11-29 11:54:10 CLIENT -> SERVER: AUTH LOGIN
    2025-11-29 11:54:10 SERVER -> CLIENT: 334 VXNlcm5hbWU6
    2025-11-29 11:54:10 CLIENT -> SERVER: [credentials hidden]
    2025-11-29 11:54:10 SERVER -> CLIENT: 334 UGFzc3dvcmQ6
    2025-11-29 11:54:10 CLIENT -> SERVER: [credentials hidden]
    2025-11-29 11:54:12 SERVER -> CLIENT: 535 5.7.8 Error: authentication failed: (reason unavailable)
    2025-11-29 11:54:12 SMTP ERROR: Password command failed: 535 5.7.8 Error: authentication failed: (reason unavailable)
    SMTP Error: Could not authenticate.
    2025-11-29 11:54:12 CLIENT -> SERVER: QUIT
    2025-11-29 11:54:12 SERVER -> CLIENT: 221 2.0.0 Bye
    2025-11-29 11:54:12 Connection: closed
    SMTP Error: Could not authenticate.

    The page I need help with: [log in to see the link]

Viewing 4 replies - 1 through 4 (of 4 total)
  • Plugin Support Patrick

    (@paddyam)

    5 months, 3 weeks ago

    Hi @frehbein,

    Thanks for reaching out to us and sorry to hear about the issue with your mailer connection setup.

    The error message you’re seeing “SMTP Error: Could not authenticate” means the SMTP server is rejecting the login attempt. For context, WP Mail SMTP simply bridges a connection between your WordPress site and your mailer service. This connection makes it so emails sent by your WordPress site are funneled over and delivered by your mailer service. For instance, if you connect WP Mail SMTP to SendLayer, emails from your site will be sent by SendLayer instead of your web host’s server. This improves the reliability and efficiency of your email to make sure your email lands in inboxes instead of spam folders or being rejected by the server.

    To assist with troubleshooting and fixing, please check to confirm that you have the correct credentials as outlined on how to setup the Other SMTP mailer.

    After making these adjustments, please send another test email. If it still fails, share the updated debug log so we can continue troubleshooting together. If you still have the error sending out the test email, you can make use of some of the SMTP test tools such as SMTPer to verify the credentials and isolate the source of the issue.

    Let us know how it goes.

    Plugin Support Patrick

    (@paddyam)

    5 months, 3 weeks ago

    Hi @frehbein,

    We haven’t heard from you in a while, so I’m going to go ahead and close out this thread for now. If you’re still having trouble, feel free to respond here at your convenience and we’ll be happy to help.

    Have a great day!

    Thread Starter frehbein

    (@frehbein)

    5 months, 1 week ago

    Hello, Patrick,

    Thank you for your help.

    I’m still having problems with the SMTP. I’m using my email to set the SMTP however the forms will be sent with another “from” email, so it will match my client’s email. Can this be the problem?

    I checked all the steps on the url you sent. I’m using a titan email from hostinger.

    This is the debug log:

    Versions:
    WordPress: 6.8.3
    WordPress MS: No
    PHP: 7.4.33
    WP Mail SMTP: 4.7.1

    Params:
    Mailer: smtp
    Constants: No
    ErrorInfo: SMTP Error: Could not authenticate.
    Host: smtp.hostinger.com
    Port: 587
    SMTPSecure:    tls
    SMTPAutoTLS:bool(true)
    SMTPAuth:bool(true)

    Server:
    OpenSSL: OpenSSL 1.1.1w 11 Sep 2023
    Apache.mod_security: No

    Debug:
    Email Source: WP Mail SMTP Mailer: Other SMTP SMTP Error: Could not authenticate.

    SMTP Debug:
    2025-12-16 18:46:36 Connection: opening to smtp.hostinger.com:587, timeout=30, options=array()
    2025-12-16 18:46:36 Connection: opened
    2025-12-16 18:46:36 SERVER -> CLIENT: 220 ESMTP smtp.hostinger.com
    2025-12-16 18:46:36 CLIENT -> SERVER: EHLO seguefa.com
    2025-12-16 18:46:36 SERVER -> CLIENT: 250-smtp.hostinger.com250-PIPELINING250-SIZE 48811212250-ETRN250-STARTTLS250-AUTH PLAIN LOGIN250-ENHANCEDSTATUSCODES250-8BITMIME250-DSN250 CHUNKING
    2025-12-16 18:46:36 CLIENT -> SERVER: STARTTLS
    2025-12-16 18:46:36 SERVER -> CLIENT: 220 2.0.0 Ready to start TLS
    2025-12-16 18:46:37 CLIENT -> SERVER: EHLO seguefa.com
    2025-12-16 18:46:37 SERVER -> CLIENT: 250-smtp.hostinger.com250-PIPELINING250-SIZE 48811212250-ETRN250-AUTH PLAIN LOGIN250-ENHANCEDSTATUSCODES250-8BITMIME250-DSN250 CHUNKING
    2025-12-16 18:46:37 CLIENT -> SERVER: AUTH LOGIN
    2025-12-16 18:46:37 SERVER -> CLIENT: 334 VXNlcm5hbWU6
    2025-12-16 18:46:37 CLIENT -> SERVER: [credentials hidden]
    2025-12-16 18:46:37 SERVER -> CLIENT: 334 UGFzc3dvcmQ6
    2025-12-16 18:46:37 CLIENT -> SERVER: [credentials hidden]
    2025-12-16 18:46:39 SERVER -> CLIENT: 535 5.7.8 Error: authentication failed: (reason unavailable)
    2025-12-16 18:46:39 SMTP ERROR: Password command failed: 535 5.7.8 Error: authentication failed: (reason unavailable)
    SMTP Error: Could not authenticate.
    2025-12-16 18:46:39 CLIENT -> SERVER: QUIT
    2025-12-16 18:46:39 SERVER -> CLIENT: 221 2.0.0 Bye
    2025-12-16 18:46:39 Connection: closed
    SMTP Error: Could not authenticate.
    • This reply was modified 5 months, 1 week ago by frehbein.
    Plugin Support Patrick

    (@paddyam)

    5 months, 1 week ago

    @frehbein

    Thanks for getting back to me.

    Looking at the log you shared, the issue is coming from the SMTP authentication step:

    535 5.7.8 Error: authentication failed

    This means Titan/Hostinger is rejecting the login details being used. I’d recommend double‑checking that the SMTP username and password match the exact Titan mailbox credentials. If you want to verify them independently, a tool like https://dnschecker.org/smtp-test-tool.php can help confirm whether the mailbox can authenticate successfully.

    Regarding the sender (From Email), it must be an authorized address — ideally the same mailbox you’re authenticating with. If you want the customer’s email to appear in the message, the best practice is to set it as the Reply‑To instead of the From address. That keeps deliverability stable and avoids SMTP rejections.

    If SMTP continues failing, I strongly recommend switching to a supported transactional mailer for reliable delivery:

    Services like SendLayer, Brevo, Mailgun, or SendGrid avoid these SMTP issues entirely.

    I hope this helps.

Viewing 4 replies - 1 through 4 (of 4 total)

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