This is the error I am getting when sending mail through my PHP code:
[Tue Nov 17 23:03:56.326593 2020] [proxy_fcgi:error] [pid 26927:tid 140160637179648] [clie
nt 188.8.131.52:62498] AH01071: Got error 'PHP message: PHP Warning: preg_replace(): Th
e /e modifier is no longer supported, use preg_replace_callback instead in /opt/bitnami/ap
ache/htdocs/funcoes/PHPMailer/class.phpmailer.php on line 1606', referer: https://www.webe
Well, the version of my PHPMailer is very ancient. It looks like if I get the latest version, the problem will be solved. I'll try doing this and, if needed, I will check the other things you suggested me to, even because I opened the port 25 following an AWS tutorial.