Obsolete, fresh ubuntu 24.04 should work out of the box with gnome-remote-desktop: 46.0-2.
If you enabled gnome-remote-desktop in ubuntu 24.04 (ubuntu noble nombat), and cannot connect and see these errors in journalctl
gnome-remote-desktop-daemon[2650]: [22:04:03:071] [2650:4874] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_CONTINUE_NEEDED [0x00090312]
gnome-remote-desktop-daemon[2650]: [22:04:03:172] [2650:4874] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_COMPLETE_NEEDED [0x00090313]
gnome-remote-desktop-daemon[2650]: [22:04:03:172] [2650:4874] [ERROR][com.winpr.sspi.NTLM] - Message Integrity Check (MIC) verification failed!
gnome-remote-desktop-daemon[2650]: [22:04:03:172] [2650:4874] [WARN][com.winpr.sspi] - CompleteAuthToken status SEC_E_MESSAGE_ALTERED [0x8009030F]
gnome-remote-desktop-daemon[2650]: [22:04:03:172] [2650:4874] [WARN][com.freerdp.core.nla] - CompleteAuthToken status SEC_E_MESSAGE_ALTERED [0x8009030F]
gnome-remote-desktop-daemon[2650]: [22:04:03:172] [2650:4874] [ERROR][com.freerdp.core.transport] - client authentication failure
gnome-remote-desktop-daemon[2650]: [22:04:03:172] [2650:4874] [ERROR][com.freerdp.core.peer] - peer_recv_callback: CONNECTION_STATE_INITIAL - rdp_server_accept_nego() fail
gnome-remote-desktop-daemon[2650]: [22:04:03:172] [2650:4874] [ERROR][com.freerdp.core.transport] - transport_check_fds: transport->ReceiveCallback() - -1
then you might look here (https://askubuntu.com/questions/1419705/gnome-remote-desktop-couldnt-retrieve-rdp-username-credentials-not-set-and),
--> set a password that only contains unicode chars. The rdp password might be different from your linux user password!