I need to adjust Email config to use office365 on port 587. However after making the change , email fails, throwing the following error:
projeqtor.php' at line (2932)
cause = mail(): SMTP server response: 451 5.7.3 STARTTLS is required to send mail [BLAPR03CA0092.namprd03.prod.outlook.com 2025-09-16T17:42:53.030Z 08DDF4198AE707FA]
2025-09-16 13:42:53.108 ** ERROR ** [V10.3.4] Error sending mail
2025-09-16 13:42:53.109 ** ERROR ** [V10.3.4] SMTP Server : smtp.office365.com
2025-09-16 13:42:53.110 ** ERROR ** [V10.3.4] SMTP Port : 587
2025-09-16 13:42:53.111 ** ERROR ** [V10.3.4] Sendmail path :
2025-09-16 13:42:53.112 ** ERROR ** [V10.3.4] Mail stored in Database : #19322
My first thought is the issue is related to SSL .
When I try to use Library PHPMailer (recommended) with the SMTP settings above I am also seeing
Extension missing: openssl.
Any help or insight would be greatly appreciated. Thank you in advance.
Fix:
In C:Program Files (x86)EasyPHP-Devserver-17eds-binariesphpphp713vc14x86x230519122821PHP.INI, un-comment extension=php_openssl.dll.
change ;extension=php_openssl.dll to extension=php_openssl.dll in your php.ini file. then restart your stack.
You have the answer
Extension missing: openssl.
You need to install this extension to use SSL encryption