I am running Xcode Server Bots on my local iMac but the email notifications are not being sent.

I have followed many tutorials and have `postfix` setup and working. I can successfully send emails using the command

```
sudo echo "Test sending email from Postfix" | mail -s "Test Postfix" xxxxxx@me.com

```

and my email is received.

Under `Xcode` > `Preferences` > `Server & Bots` > `Mail` I have left everything blank as per all the tutorials.

For my Bot, under `Triggers` I have a `Periodic Email Report` with `Schedule` set to `After each integration` and set my `from`, `reply-to` and `To` fields and have every `Notify On` ticked.

[![enter image description here](https://i.stack.imgur.com/s3fsr.png)](https://i.stack.imgur.com/s3fsr.png)

I monitor the `smtp` and `smtp` process using the command

```
sudo log stream --predicate  '(process == "smtpd") || (process == "smtp")' --info

```

and when I send an email using the above test, I get a log line showing.

However when my Xcode Bot completes, I get absolutely nothing.
The Bot logs show

```
Feb  2 13:47:16  [596] <Info>: Executing trigger 'Periodic Email Report'
Feb  2 13:47:16  [596] <Info>: Executing trigger 'New Issue Email'

```

So the email report is not triggering any kind of `smtp`. Is it even using postfix? Can I log something else to see whether it is hitting `postfix` at all?

EDIT ------

I have found some `sendmail` logs that seem to show Xcode doesn't have the right permission to use `postdrop`:

```
kernel    Sandbox: sendmail(48548) deny(1) forbidden-exec-sugid
sendmail    fatal: execvp /usr/sbin/postdrop: Operation not permitted
sendmail    warning: command "/usr/sbin/postdrop -r" exited with status 1
sendmail    fatal: xcode@<redacted>.com(450): unable to execute /usr/sbin/postdrop -r: Undefined error: 0

```

My `postdrop` permissions seem to be correct compared to what I can find online:

```
-rwxr-xr-x    1 root   wheel        570448  1 Jan  2020 postalias
-rwxr-xr-x    1 root   wheel        466416  1 Jan  2020 postcat
-rwxr-xr-x    1 root   wheel        823488  1 Jan  2020 postconf
-rwxr-sr-x    1 root   _postdrop    588624  1 Jan  2020 postdrop
-rwxr-xr-x    1 root   wheel        431904  1 Jan  2020 postfix
-rwxr-xr-x    1 root   wheel        432032  1 Jan  2020 postkick
-rwxr-xr-x    1 root   wheel        449424  1 Jan  2020 postlock
-rwxr-xr-x    1 root   wheel        431872  1 Jan  2020 postlog
-rwxr-xr-x    1 root   wheel        569632  1 Jan  2020 postmap
-rwxr-xr-x    1 root   wheel        465872  1 Jan  2020 postmulti
-rwxr-sr-x    1 root   _postdrop    588448  1 Jan  2020 postqueue
-rwxr-xr-x    1 root   wheel        466784  1 Jan  2020 postsuper

```

I have the `_postdrop` user in my `/etc/group` file as:

```
_postdrop:*:28:

```

Or am I reading this wrong? Does `sendmail` user need permission to use `postdrop`?

EDIT 2 -------

It seems this might be an issue with `Big Sur` making the root partition read only. `sudo postfix set-permissions` can't do it's thing.

So I guess the question now is, how to install/use a different method for Xcode Server to send emails?