KRDC / KRDP woes -- cannot establish connection to another KDE PC

I’m trying to establish a connection to a KDE 6.4.5/Wayland PC with krdp installed. Systems tried were mstsc on Win10 and another KDE PC with KDE 6.5 and krdc. Both fail to connect.

The result of journalctl -x -b | grep krdc is:

Okt 25 12:35:58 M4800 systemd[1433]: Started app-org.kde.krdc@1190423271a245219c254f848a9c6ac4.service - KRDC - Verbindung zu entferntem Rechner.
Okt 25 12:36:04 M4800 dbus-daemon[1454]: [session uid=1000 pid=1454 pidfd=5] Activating service name='org.kde.kwalletd6' requested by ':1.69' (uid=1000 pid=2755 comm="/usr/bin/krdc -qwindowtitle KRDC" label="unconfined")
Okt 25 12:36:04 M4800 krdc[2755]: KRDC: Starting RDP session
Okt 25 12:36:04 M4800 krdc[2755]: [12:36:04:559] [2755:00000ae0] [WARN][com.freerdp.crypto] - [verify_cb]: Certificate verification failure 'self-signed certificate (18)' at stack position 0
Okt 25 12:36:04 M4800 krdc[2755]: [12:36:04:559] [2755:00000ae0] [WARN][com.freerdp.crypto] - [verify_cb]: C = AU, ST = Some-State, O = Internet Widgits Pty Ltd
Okt 25 12:36:09 M4800 krdc[2755]: [12:36:09:048] [2755:00000ae0] [ERROR][com.winpr.sspi.Kerberos] - [kerberos_AcquireCredentialsHandleA]: krb5_parse_name (Configuration file does not specify default realm [-1765328160])
Okt 25 12:36:09 M4800 krdc[2755]: [12:36:09:048] [2755:00000ae0] [ERROR][com.winpr.sspi.Kerberos] - [kerberos_AcquireCredentialsHandleA]: krb5_parse_name (Configuration file does not specify default realm [-1765328160])
Okt 25 12:36:09 M4800 krdc[2755]: [12:36:09:146] [2755:00000ae0] [WARN][com.freerdp.core.connection] - [rdp_client_connect_auto_detect]: expected messageChannelId=1008, got 1003
Okt 25 12:36:09 M4800 krdc[2755]: [12:36:09:146] [2755:00000ae0] [WARN][com.freerdp.core.license] - [license_read_binary_blob_data]: license binary blob::type BB_ERROR_BLOB, length=0, skipping.
Okt 25 12:36:09 M4800 krdc[2755]: [12:36:09:148] [2755:00000ae0] [WARN][com.freerdp.core.connection] - [rdp_client_connect_auto_detect]: expected messageChannelId=1008, got 1003
Okt 25 12:36:09 M4800 krdc[2755]: [12:36:09:183] [2755:00000ae0] [ERROR][com.freerdp.core] - [rdp_set_error_info]: ERRINFO_LOGOFF_BY_USER [0x0001000C]
Okt 25 12:36:09 M4800 krdc[2755]: [12:36:09:183] [2755:00000ae0] [ERROR][com.freerdp.core.rdp] - [rdp_recv_callback_int][0x5a90d1e70dd0]: CONNECTION_STATE_CAPABILITIES_EXCHANGE_DEMAND_ACTIVE status STATE_RUN_QUIT_SESSION [-2]
Okt 25 12:36:09 M4800 krdc[2755]: [12:36:09:183] [2755:00000ae0] [ERROR][com.freerdp.core.transport] - [transport_check_fds]: transport_check_fds: transport->ReceiveCallback() - STATE_RUN_QUIT_SESSION [-2]

I have no idea what’s going wrong here.

Is there a need to enter a domain? I tried, fails with or without. Since neither the MS Windows PC nor the KDE PC can connect, the issue should be on the krdp side, but there’s little to configure. Restarts and logouts didn’t rectify this.

What can be done to establish a connection? I am using the IP address for the target PC.