Node monitoring tool (email plugin) doesn't work

Build Info:
indy-node 1.2.50 (rc)

Steps to Reproduce:
0. Install pool and make the following steps on any node.
1. apt-get install sendmail
2. Check that it works: `echo "Subject: sendmail test" | sendmail -v youremail@
example.com -f alert@noreply.com`
3. pip3 install sovrinnotifieremail
4. Add `SOVRIN_NOTIFIER_EMAIL_RECIPIENTS=
youremail@example.com` to your /etc/environment
5. Check messages about events emitted by pool (node).

Actual Results:
There are no messages about pool (node) activity.

Expected Results:
The tool should work as it described in manual (in attachment).