Client: ValueError: FLEETSPEAK_COMMS_CHANNEL_INFD is not set

Environment

The GRR is installed on a VM running on ESXi on-prem. The VM runs Ubuntu 18.04 and GRR was installed from DEB (using the official documentation)
GRR Version is 3.4.6.0
Ubuntu 18.04
OpenSuse Leap 15

**Describe the issue**
We are currently testing GRR and tried to run the rpm package on Linux OpenSuse (leap 15).
The package does not run automatically. So when I have tried to run it manually using the command:

e09d8dd5bdf4:/usr/lib64/grr/grr_3.4.6.0_amd64 # grrd --config=grrd.yaml --verbose

It has thrown me this error:

e09d8dd5bdf4:/usr/lib64/grr/grr_3.4.6.0_amd64 # grrd --config=grrd.yaml --verbose
I0608 08:06:36.050097 139777080503168 client_logging.py:113] Writing log file to /var/log/GRRlog.txt
INFO:2022-06-08 08:06:36,050 client_logging:113] Writing log file to /var/log/GRRlog.txt
Traceback (most recent call last):
File "grr_response_client/client.py", line 36, in
File "absl/app.py", line 299, in run
File "absl/app.py", line 250, in _run_main
File "grr_response_client/client_main.py", line 89, in main
File "grr_response_client/fleetspeak_client.py", line 66, in __init__
File "fleetspeak/client_connector/connector.py", line 108, in __init__
File "fleetspeak/client_connector/connector.py", line 63, in _EnvOpen
ValueError: FLEETSPEAK_COMMS_CHANNEL_INFD is not set
[678] Failed to execute script client

FLEETSPEAK_COMMS_CHANNEL_INFD is not set - what is this error means?
I have seen on github people writing that changing the mysql max size limit to 50 and then back to 40 fixes this issue. But first of all, for me this sounds like not the logical idea, but I have tested it and as expected - it didn't resolve the issue...