I just configured a Gmail account including the lines that our documentation mentions (but using the
/opt/bitnami/apps/mantis/htdocs/config/config_inc.php file, thank you for reporting this) and everything went fine. I tested the password recovery method and I received an email to recover the password
For troubleshooting SMTP issues, we have an SMTP Checker: It will analyse your SMTP configuration in your application (currently supported apps: wordpress & redmine). It will show which SMTP configuration your application is using and whether the connection with the SMTP server is good and will also check the mail delivery.
Execute these commands inside your instance (connect through SSH or using the console) to download the tool:
chmod +x smtp-checker-v2.0.0-linux-amd64
Since your application is not supported yet, please find out your SMTP settings and run the command:
./smtp-checker-v2.0.0-linux-amd64 -smtp_host YOUR_SMTP_HOST -smtp_port YOUR_SMTP_PORT -smtp_user YOUR_SMTP_USER -smtp_password YOUR_SMTP_PASS -mail_recipient YOUR_MAIL_ACCOUNT
Please note that you need to replace the placeholders YOUR_SMTP_HOST, YOUR_SMTP_PORT, YOUR_SMTP_USER, YOUR_SMTP_PASS and YOUR_MAIL_ACCOUNT with the actual values you want to use.
Please show us the results of executing the commands.