Hi @fftfaisal,
Wordpress have changed PHPMailer since version 5.5 (See https://github.com/Birmania/smtp-mailing-queue/issues/3), this is why you get all these deprecation warnings.
You can get rid of it by updating “SMTP Mailing Queue” to its new version : v1.4.0 which include compatibility code.
These deprecation warnings should not broke the periodic email sending. Do you use external cron job (with secret key) or native wordpress cron process ?
If external : Ensure that your cron server is still running and that secret key is right.
If internal : Problem can result from not enough wp-cron execution (meaning not enough visitor on the website). If you wqant to remove this limitation on your website, see topics about real cron job execution through “DISABLE_WP_CRON” flag.
Also this ‘datetimezone’ error is strange, it may come from a PHP misconfiguration.
Do you have any details (trace of the error) about this ?
Yours faithfully,
Birmania