Cron not working on wordpress hosted on AWS lightsail

It started with WP-offload Ses throwing a message that cron is not working so mails are in que. Then I downloaded WP Crontrol plugin which has below error message

……There was a problem spawning a call to the WP-Cron system on your site. This means WP-Cron events on your site may not work. The problem was:

Unexpected HTTP response code: 403……

Manually firing the cron events does not also work.

Even tried to disable cron in config.php by using define(‘DISABLE_WP_CRON’, true); but it didn’t help

Even changed permissions for file /opt/bitnami/wordpress/wp-cron.php to 755 but it didn’t solve anything

Later tried adding below line through ssh using comand crontab -e but it also did not do anything

*/5 * * * * cd /opt/bitnami/wordpress; php -q wp-cron.php >/dev/null 2>&1

Not sure if this is wordpress issue or aws lightsail issue. Now our emails are not going, Wp rocket isn’t optimizing database, and many things are just stuck

If you anyone can please suggest what can be done, would be greatful

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