OpenWRT 21.02: radicale2 not working

I'm trying to get radicale2 running on by FB4040, but it does not work. After configuring (using Luci), I try to start the server by

/etc/init.d/radicale2 start

Using "ps | grep radicale" I can see that the process runs for aprox 2 second and then it will stop:

root@fb4040:~# ps | grep radi
18155 radicale  8476 R    {radicale2} /usr/bin/python3 /usr/bin/radicale2 --config=/etc/radicale2/conf
18180 root      1100 S    grep radi

When I start the daemon manually, I get some strange error:

root@fb4040:~# /usr/bin/python3 /usr/bin/radicale2 --config=/etc/radicale2/config
ERROR: Failed to start logger: Failed to load logging configuration file '/tmp/log/radicale': 'formatters'
Traceback (most recent call last):
  File "/usr/lib/python3.9/site-packages/radicale/", line 56, in start
  File "/usr/lib/python3.9/site-packages/radicale/", line 32, in configure_from_file
  File "/usr/lib/python3.9/logging/", line 71, in fileConfig
  File "/usr/lib/python3.9/logging/", line 104, in _create_formatters
  File "/usr/lib/python3.9/", line 963, in __getitem__
KeyError: 'formatters'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/bin/radicale2", line 33, in <module>
    sys.exit(load_entry_point('Radicale==2.1.11', 'console_scripts', 'radicale')())
  File "/usr/lib/python3.9/site-packages/radicale/", line 116, in run
  File "/usr/lib/python3.9/site-packages/radicale/", line 58, in start
RuntimeError: Failed to load logging configuration file '/tmp/log/radicale': 'formatters'

What is wrong? What did I miss?

I would have hoped for at least a little response...

Did anyone get radicale working on their OpenWRT machine?

How can I at least make radicale2 more verbose, eg. make it use the log file? No matter what file I choose as log file, not a single character will apeare in it when I try to start the program.

So, please: if someone has a working configuration, would you share it with me? I am really getting frustrated over not being able to make this thing work.