Initial simple test fails. Ver 3.0.20 from Ubuntu

[Pavel Aronsky]

Dear experts,

I'm very sorry for a lame help request but really don't know what else to do.
I want to try the simplest setup for some small (embedded) client.
So decided to begin with MD5 and username-password.

Installed freeradius in Win11 WSL environment, Ubuntu 20.04.6 LTS, via
apt install as usual.
It brings version 3.0.20.

As advised in "getting started" docum, made no changes anywhere
besides adding a user and a client.

In /etc/freeradius/3/0/users: at beginning:
(which is symlnk to mods-config/files/authorize)

JIG46 Cleartext-Password := "secret"

In /etc/freeradius/3/0/clients.conf: after the existing localhost:

client myswitch {
       ipaddr          = 10.183.0.110
       secret          = testing123
       require_message_authenticator = no
       proto = *
       nas_type = other
}

Then started the server on localohst and port 1645 (because the
default port appears to be busy):

sudo freeradius -X -xx -p 1645 -i localhost

Then run :  radtest -x  -t eap-md5 JIG46 secret localhost:1645 0 testing123

Output:

Loading input data...
including dictionary file /usr/share/freeradius/dictionaryReading
input vps from stdin
Read 1 element(s) from input: stdin
Loaded: 1 input element(s).
Adding new socket: src: 0.0.0.0:0, dst: 127.0.0.1:1645
Added new socket: 5 (num sockets: 1)
Transaction: 0, sending packet: 0 (id: 151)...
Sent Access-Request Id 151 from 0.0.0.0:59783 to 127.0.0.1:1645 length 69
        User-Name = "JIG46"
        Cleartext-Password = "secret"
        NAS-IP-Address = 127.0.1.1
        NAS-Port = 0
        Message-Authenticator = 0x00
        EAP-Code = Response
        EAP-Type-Identity = 0x4a49473436
        EAP-Message = 0x024d000a014a49473436
Timeout for transaction: 0, tries (so far): 1 (max: 3)Transaction: 0,
sending packet: 1 (id: 151)...
............ two more tries......
Timeout for transaction: 0, tries (so far): 3 (max: 3)No response for
transaction: 0, giving upDeallocating (sockfd: 5, id: 151)
Main loop: done.

The server refuses to start EAP handshake - I don't see any errors due
to unknown usernames or wrong passwords?

Exactly the same outcome with a real client (a managed switch, with
the client id myswitch, defined above).

*** The complete log is here.
https://gist.github.com/pavel-a/7b0c0c230ad28627218eade7fb0d1c61

Please advise? Is this because of WSL or something wrong in the configuration??

*** Windows firewall is OFF.

- ddbug