What role does restarting the Apache server play in resolving mail server connection issues in PHP applications?

When encountering mail server connection issues in PHP applications, restarting the Apache server can help resolve the problem. This is because restarting Apache can refresh the server's configuration settings, including any changes made to the mail server connection settings in the PHP application. By restarting Apache, any lingering connection issues or conflicts may be resolved, allowing the PHP application to successfully connect to the mail server.

// Code snippet to restart Apache server using PHP
exec('sudo service apache2 restart');