how-to-debug-smtp-mail-in-joomla-4

Go to Home Dashboard → Site → Plugins. Enable the System - Debug plugin and configure it with the following setting, which restricts the debug output to your own login session at both the Backend and the Frontend. If you do not want to login to the Frontend as Super User, create a unique user group for your testing activities and select that user group from the list of allowed user groups:

• Allowed Groups: Super Users

Save this setting.

Go to Home Dashboard → System → Global Configuration → System tab → Debug. Set Debug System to Yes.

Go to Home Dashboard → System → Global Configuration → Server tab. Set Error Reporting to Maximum.

Go to Home Dashboard → System → Global Configuration → Logging tab. Note the contents of Path to Log Folder, usually [something]/administrator/logs. Also select Log Almost Everything.

Go to the Custom logging section and the Log Categories field. Enter mail (no quotation marks) into this field.

Save the settings.

In Home Dashboard → System → Global Configuration → Server tab, press Send Test Email. Alternatively, log into the Frontend using your user name in the unique user group meant for testing activities and perform the function that will send an email.

Once the testing is finished, download the log file administrator/logs/everything.php. If the website was migrated from Joomla 2.5, the log file everything.php may reside in the logs folder at the top level of the Joomla folder.