Title: PHP Fatal Error
Last modified: May 14, 2026

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# PHP Fatal Error

 *  [Mike Meinz](https://wordpress.org/support/users/mikemeinz/)
 * (@mikemeinz)
 * [3 weeks, 3 days ago](https://wordpress.org/support/topic/php-fatal-error-503/)
 * I got these errrors in the error_log file after activating the **WP SMTP Mailer–
   SMTP7** plugin, entering SMTP parameters and attempting to login to [https://SITENAME.com/wp-admin](https://SITENAME.com/wp-admin).
   I use [**Admin Safety Guard** ](https://wordpress.org/plugins/admin-safety-guard/)
   plugin to send a One-Time-Password email message. 
   After clicking the Log In 
   button, the next page (the OTP input page) never displayed. AFter a timeout, 
   the error 504 page was displayed. Deactivtating the **WP SMTP Mailer – SMTP7**
   plugin returned our website to normal behavior.
 *     ```wp-block-code
       Stack trace:#0 /home/SITENAME/public_html/wp-includes/class-wp-hook.php(341): wpmsm_mail_form()#1 /home/SITENAME/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters()#2 /home/SITENAME/public_html/wp-includes/pluggable.php(435): apply_filters()#3 /home/SITENAME/public_html/wp-content/plugins/admin-safety-guard/app/Classes/Features/TwoFactorAuth.php(356): wp_mail()#4 /home/SITENAME/public_html/wp-content/plugins/admin-safety-guard/app/Classes/Features/TwoFactorAuth.php(288): ThemePaste\SecureAdmin\Classes\Features\TwoFactorAuth->send_mail()#5 /home/SITENAME/public_html/wp-includes/class-wp-hook.php(341): ThemePaste\SecureAdmin\Classes\Features\TwoFactorAuth->intercept_login_with_otp()#6 /home/SITENAME/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters()#7 /home/SITENAME/public_html/wp-includes/pluggable.php(702): apply_filters()#8 /home/SITENAME/public_html/wp-includes/user.php(109): wp_authenticate()#9 /home/SITENAME/public_html/wp-login.php(1323): wp_signon()#10 {main}  thrown in /home/SITENAME/public_html/wp-content/plugins/wp-mail-smtp-mailer/wp-mail-smtp-mailer.php on line 113[14-May-2026 13:18:45 UTC] PHP Fatal error:  Uncaught TypeError: Cannot access offset of type string on string in /home/SITENAME/public_html/wp-content/plugins/wp-mail-smtp-mailer/wp-mail-smtp-mailer.php:113Stack trace:#0 /home/SITENAME/public_html/wp-includes/class-wp-hook.php(341): wpmsm_mail_form()#1 /home/SITENAME/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters()#2 /home/SITENAME/public_html/wp-includes/pluggable.php(435): apply_filters()#3 /home/SITENAME/public_html/wp-includes/class-wp-recovery-mode-email-service.php(225): wp_mail()#4 /home/SITENAME/public_html/wp-includes/class-wp-recovery-mode-email-service.php(62): WP_Recovery_Mode_Email_Service->send_recovery_mode_email()#5 /home/SITENAME/public_html/wp-includes/class-wp-recovery-mode.php(185): WP_Recovery_Mode_Email_Service->maybe_send_recovery_mode_email()#6 /home/SITENAME/public_html/wp-includes/class-wp-fatal-error-handler.php(55): WP_Recovery_Mode->handle_error()#7 [internal function]: WP_Fatal_Error_Handler->handle()#8 {main}  thrown in /home/SITENAME/public_html/wp-content/plugins/wp-mail-smtp-mailer/wp-mail-smtp-mailer.php on line 113[14-May-2026 13:18:54 UTC] PHP Fatal error:  Uncaught TypeError: Cannot access offset of type string on string in /home/SITENAME/public_html/wp-content/plugins/wp-mail-smtp-mailer/wp-mail-smtp-mailer.php:113Stack trace:#0 /home/SITENAME/public_html/wp-includes/class-wp-hook.php(341): wpmsm_mail_form()#1 /home/SITENAME/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters()#2 /home/SITENAME/public_html/wp-includes/pluggable.php(435): apply_filters()#3 /home/SITENAME/public_html/wp-content/plugins/admin-safety-guard/app/Classes/Features/TwoFactorAuth.php(356): wp_mail()#4 /home/SITENAME/public_html/wp-content/plugins/admin-safety-guard/app/Classes/Features/TwoFactorAuth.php(288): ThemePaste\SecureAdmin\Classes\Features\TwoFactorAuth->send_mail()#5 /home/SITENAME/public_html/wp-includes/class-wp-hook.php(341): ThemePaste\SecureAdmin\Classes\Features\TwoFactorAuth->intercept_login_with_otp()#6 /home/SITENAME/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters()#7 /home/SITENAME/public_html/wp-includes/pluggable.php(702): apply_filters()#8 /home/SITENAME/public_html/wp-includes/user.php(109): wp_authenticate()#9 /home/SITENAME/public_html/wp-login.php(1323): wp_signon()#10 {main}  thrown in /home/SITENAME/public_html/wp-content/plugins/wp-mail-smtp-mailer/wp-mail-smtp-mailer.php on line 113
       ```
   

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## Tags

 * [php-error](https://wordpress.org/support/topic-tag/php-error/)

 * 0 replies
 * 1 participant
 * Last reply from: [Mike Meinz](https://wordpress.org/support/users/mikemeinz/)
 * Last activity: [3 weeks, 3 days ago](https://wordpress.org/support/topic/php-fatal-error-503/)
 * Status: not resolved