Improve docs regarding mail debugging (#555)

Author: dmohns

docs/installation/environment-variables.md

@@ -137,17 +137,17 @@ Slack
 Configure the following environment variable to enable MicroPowerManager to send email via SMTP.
 These configure instance level email sent to tenants, for example signup confirmation, password reset, etc...
 
-| Environment Variable        | Default                                        | Description                                                                                                                                     |
-| --------------------------- | ---------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- |
-| `MAIL_SMTP_HOST`            | `smtp.mailgun.org`                             | Mail server hostname. For example `smtp.mailserver.com`.                                                                                        |
-| `MAIL_SMTP_PORT`            | `587`                                          | Mail server port.                                                                                                                               |
-| `MAIL_SMTP_ENCRYPTION`      | `tls`                                          | Mail encryption.                                                                                                                                |
-| `MAIL_SMTP_AUTH`            | `false`                                        | Whether to use SMTP Auth.                                                                                                                       |
-| `MAIL_USERNAME`             | **Required** (when `MAIL_SMTP_AUTH` is `true`) | The username used in SMTP Auth.                                                                                                                 |
-| `MAIL_PASSWORD`             | **Required** (when `MAIL_SMTP_AUTH` is `true`) | The password used in SMTP Auth.                                                                                                                 |
-| `MAIL_SMTP_DEFAULT_SENDER`  | **Required**                                   | The email used in `from` and `replyTo` fields of sent email. Note: Depending on the mailserver this might be different from SMTP Auth username. |
-| `MAIL_SMTP_DEFAULT_MESSAGE` | `Please do not reply to this email`            | Default message body of emails.                                                                                                                 |
-| `MAIL_SMTP_DEBUG_LEVEL`     | `0`                                            | Debug level used in [PHPMailer](https://github.com/PHPMailer/PHPMailer/). `0` No output, `4` Noisy, low-level data output, rarely needed.       |
+| Environment Variable        | Default                                        | Description                                                                                                                                                                 |
+| --------------------------- | ---------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `MAIL_SMTP_HOST`            | `smtp.mailgun.org`                             | Mail server hostname. For example `smtp.mailserver.com`.                                                                                                                    |
+| `MAIL_SMTP_PORT`            | `587`                                          | Mail server port.                                                                                                                                                           |
+| `MAIL_SMTP_ENCRYPTION`      | `tls`                                          | Mail encryption.                                                                                                                                                            |
+| `MAIL_SMTP_AUTH`            | `false`                                        | Whether to use SMTP Auth.                                                                                                                                                   |
+| `MAIL_USERNAME`             | **Required** (when `MAIL_SMTP_AUTH` is `true`) | The username used in SMTP Auth.                                                                                                                                             |
+| `MAIL_PASSWORD`             | **Required** (when `MAIL_SMTP_AUTH` is `true`) | The password used in SMTP Auth.                                                                                                                                             |
+| `MAIL_SMTP_DEFAULT_SENDER`  | **Required**                                   | The email used in `from` and `replyTo` fields of sent email. Note: Depending on the mailserver this might be different from SMTP Auth username.                             |
+| `MAIL_SMTP_DEFAULT_MESSAGE` | `Please do not reply to this email`            | Default message body of emails.                                                                                                                                             |
+| `MAIL_SMTP_DEBUG_LEVEL`     | `0`                                            | Debug level used in [PHPMailer](https://github.com/PHPMailer/PHPMailer/blob/master/src/SMTP.php#L116-L126). `0` No output, `4` Noisy, low-level data output, rarely needed. |
 
 ### MPM Plugins
 

src/backend/app/Helpers/MailHelper.php

@@ -30,6 +30,7 @@ private function configure(): void {
         $this->mailer->Password = $this->mailSettings['password'];
         $this->mailer->From = $this->mailSettings['default_sender'];
         $this->mailer->SMTPDebug = $this->mailSettings['debug_level'];
+        // https://github.com/EnAccess/micropowermanager/issues/554
         $this->mailer->Debugoutput = 'error_log';
         $this->mailer->isSMTP();
         // When debugging Email sending locally it might helpful to explicitly set a Hostname