SMTP error even though all credentials are correct

Hi @boompronto17

As you mentioned it appears that you are attempting to connect to the smtp.postmarkapp.com SMTP server.

Did you at any time try connecting to this server? Because what immediately comes to mind is that this might be a caching issue.

Please try clearing your website cache, then back up or make a note of your WP Mail SMTP settings, because we’d like you to try fully uninstalling and re-installing WP Mail SMTP by ensuring that the checkbox mentioned in our documentation is ticked.

Please then attempt to connect to your SMTP server once more.

Hi @dakeg ,

I already follow your instruction but it returns the same result, the plugin keep connect to smtp.postmarkapp.com. I can confirm that the setting was set to Mandril on both setting page and data entries inside the wp_option table, but the error log is showing smtp.postmarkapp.com

Any other thing we could try to recheck?

Hi @boompronto17

Thanks for getting back to us.

In that case, based on the error log something may be overwriting the PHPMailer configuration.

We assume your client’s website host might have MU plugins installed or they may have modified the wp-config.php file. Can you check if there are any references to phpmailer or MailCatcher in their wp-config.php file?

@dakeg

Thanks for the clue, we found a overwriting PHP inside the functions.php file from the custom theme of this client, and the issue was fixed after we remove that code.

I really appreciate your help here, you can close this topic now.

Hi @boompronto17

You’re welcome, we’re happy to hear that you were able to confirm and resolve the issue.