Hey I am getting this issue and its really bothering me
Jun 17 10:02:12 mail nextcloud[13127]: {"reqId":"O7tUtrMSPSEBkP0j2SSW","level":4,"time":"2020-06-17T09:02:12+00:00","remoteAddr":"2603:9000:b304:5210:11bd:7ca0:110e:d10b","user":"matt@meatt@meatcupgames.com","app":"mail","method":"POST","url":"/index.php/apps/mail/api/accounts/1/send","message":"Sending mail failed: Could not send message: Could not open secure TLS connection to the server.","userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36","version":"18.0.6.0"}
Jun 17 10:02:12 mail nextcloud[13127]: {"reqId":"O7tUtrMSPSEBkP0j2SSW","level":3,"time":"2020-06-17T09:02:12+00:00","remoteAddr":"2603:9000:b304:5210:11bd:7ca0:110e:d10b","user":"matt@meatcupgames.com","app":"mail","method":"POST","url":"/index.php/apps/mail/api/accounts/1/send","message":"{\"Exception\":\"OCA\\\\Mail\\\\Exception\\\\ServiceException\",\"Message\":\"Could not send message: Could not open secure TLS connection to the server.\",\"Code\":100,\"Trace\":[{\"file\":\"/var/www/nextcloud/apps/mail/lib/Controller/AccountsController.php\",\"line\":345,\"function\":\"sendMessage\",\"class\":\"OCA\\\\Mail\\\\Service\\\\MailTransmission\",\"type\":\"->\",\"args\":[{\"__class__\":\"OCA\\\\Mail\\\\Model\\\\NewMessageData\"},null,null,8]},{\"file\":\"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php\",\"line\":170,\"function\":\"send\",\"class\":\"OCA\\\\Mail\\\\Controller\\\\AccountsController\",\"type\":\"->\",\"args\":[1,\"sas\",\"asas\",\"matthewtrek@gmailc.om\",\"\",\"\",false,8,null,null,[],null]},{\"file\":\"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php\",\"line\":99,\"function\":\"executeController\",\"class\":\"OC\\\\AppFramework\\\\Http\\\\Dispatcher\",\"type\":\"->\",\"args\":[{\"__class__\":\"OCA\\\\Mail\\\\Controller\\\\AccountsController\"},\"send\"]},{\"file\":\"/var/www/nextcloud/lib/private/AppFramework/App.php\",\"line\":125,\"function\":\"dispatch\",\"class\":\"OC\\\\AppFramework\\\\Http\\\\Dispatcher\",\"type\":\"->\",\"args\":[{\"__class__\":\"OCA\\\\Mail\\\\Controller\\\\AccountsController\"},\"send\"]},{\"file\":\"/var/www/nextcloud/lib/private/AppFramework/Routing/RouteActionHandler.php\",\"line\":47,\"function\":\"main\",\"class\":\"OC\\\\AppFramework\\\\App\",\"type\":\"::\",\"args\":[\"OCA\\\\Mail\\\\Controller\\\\AccountsContrroller\",\"send\",{\"__class__\":\"OC\\\\AppFramework\\\\DependencyInjection\\\\DIContainer\"},{\"accountId\":\"1\",\"_route\":\"mail.accounts.send\"}]},{\"function\":\"__invoke\",\
…etc
dns settings