Generally:
Specifically:
This could be the cause:
There might be an extraneous file in folder /usr/local/etc/torrc.d such as /usr/local/etc/torrc.d/50_user.conf~ (trailing tilde symbol) which was created by an editor as a backup file.
For debugging, run:
ls -la /etc/torrc.d
ls -la /usr/local/etc/torrc.d
And post output here.
To fix, try this command:
sudo /usr/lib/anon-gw-anonymizer-config/torrc-d-cleaner
And post output here.