SMTP Error: Could not authenticate.

Hi @rickaero,

When you get a chance, could you please share a full error log recorded when you send a test email from WP Mail SMTP > Email Test? Here’s a screenshot for the option to get a full error log. This will give us an idea of what might be going on.

Thanks!

Hi @rickaero – we haven’t heard from you in about a week, so I’m going to go ahead and mark this ticket resolved. If you still have questions, though, please feel welcome to continue the conversation.

Hi there,

I got same problem started sometime ago (this year Sept/Oct).

Find details below:

WP:5.8.2
PHP:7.4.26
WP Mail:3.2.1
Email: Other SMTP – gmail with App Password (gmail handles our domain for outgoing emails)- Settings: smtp.gmail.com, TLS, Auth ON

– Test emails are working fine, even I recreated a new password
– It is not all the time fails to send, but mostly. (WP Core succeed, WFence yes/no, WPBackup Fails)
– Did not reinstall yet the WP Mail

Error Event:
Content
Mailer: Other SMTP SMTP Error: Could not authenticate.
Source
Wordfence Security
/home/customer/www/ourdomain.com/public_html/wp-content/plugins/wordfence/lib/wordfenceClass.php (line: 7161)

wfConfig::set('lastEmailHash', time() . ':' . $hash);
		foreach ($emails as $email) {
			$uniqueContent = $content . "\n\n" . sprintf(/* translators: WordPress admin panel URL. */ __('No longer an administrator for this site? Click here to stop receiving security alerts: %s', 'wordfence'), wfUtils::getSiteBaseURL() . '?_wfsf=removeAlertEmail&jwt=' . wfUtils::generateJWT(array('email' => $email)));
			wp_mail($email, $subject, $uniqueContent);

7161 line is the last

Other Error Event:

Content
Mailer: Other SMTP SMTP Error: Could not authenticate.
Source
BackWPup
/home/customer/www/ourdomain.com/public_html/wp-content/plugins/backwpup/inc/class-job.php (line: 1152)

if ( $bracket_pos === false || $at_pos === false ) {
						$this->job['mailaddresssenderlog'] = str_replace( array(
								'<',
								'>',
							),
								'',
								$this->job['mailaddresssenderlog'] ) . ' <' . get_bloginfo( 'admin_email' ) . '>';
					}

					$headers[] = 'From: ' . $this->job['mailaddresssenderlog'];
				}
				wp_mail( $this->job['mailaddresslog'], $subject, file_get_contents( $this->logfile ), $headers );

Last line

Debug event when WFence succeed:

Content
An email request was sent.
Source
Wordfence Security
/home/customer/www/ourdomain.com/public_html/wp-content/plugins/wordfence/lib/wfActivityReport.php (line: 508)

if (!wp_mail($email, sprintf(/* translators: 1. Site URL. 2. Localized date. */ __('Wordfence activity for %1$s on %2$s', 'wordfence'), date_i18n(get_option('date_format')), $shortSiteURL), $uniqueContent, 'Content-Type: text/html')) {
				$success = false;

Hi @kemeng,

Thanks for the details! Are you using SMTP settings with constants in wp-config.php? In that case, please make sure to add the constants above the line that reads:

/* That’s all, stop editing! Happy publishing. */

Hi there,

Got free version of WP Mail and has only the password set in wp-config, in my memory.

You meant I shoud (re)configure in wp-config everything (not only password) instead of using the Plugin’s settings in WP admin?

Will check in a few days the exact lines added, im right now on a short mototrip.

Cheers,
Gabor

Hi @kemeng,

I apologize for the confusion. You don’t need to configure everything in wp-config.php. Just make sure the SMTP password (or other constants) you’re using are placed above the line that reads:

/* That’s all, stop editing! Happy publishing. */

I hope this clarifies!

Hi there,

I responded here

cheers!