Remmina on Ubuntu 20.04 is unable to RDP to Windows 10 Server

Question

I am trying to use Remmina on my Ubuntu 20.04 to RDP to a Windows 10 Server but it kept failing with "Cannot connect to the " " RDP server". I have looked for answers online have tried all of these things but it still doesn't work:

1. Removing ~/.freerdp/known_host: I am unable to find such file or even directory. The only similar directory I have is ~/.config/freerdp and when I looked at that folder there is no such known_host file.
2. Go to advance tab and change security protocol negotiation to TSL/RDP/... : I have tried all of the options and none of it works

Furthermore, I am sure that the server works since I was able to RDP to it using my friends' laptop with Ubuntu 16.04 Remmina and my laptop's Windows 10 remote desktop (dual boot). Hence I have no idea what is the problem here. I was thinking that there is something off with my network setting on Ubuntu but not sure what to check.

Can someone please advice me on what to do next? Thank so much!

Remmina version: 1.4.7, freerdp version: 2.2.0

below is the debug log

** (org.remmina.Remmina:11009): DEBUG: 21:19:51.180: [precommand] (null)
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.181: [precommand] updated to: 
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.182: (remmina_rdp_main) - Not using system proxy settings
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.182: (remmina_rdp_tunnel_init) - Tunnel init
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.182: SSH tunnel initialization…
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.183: server: 172.**.***.**, port: 3389
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.183: (remmina_rdp_tunnel_init) - protocol_plugin_start_direct_tunnel() returned [172.**.***.**]:3389
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.183: (remmina_rdp_tunnel_init) - Tunnel has been optionally initialized. Now connecting to 172.**.***.**:3389
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.183: (remmina_rdp_main) - proxy_type: (null)
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.183: (remmina_rdp_main) - proxy_username: (null)
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.183: (remmina_rdp_main) - proxy_password: (null)
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.183: (remmina_rdp_main) - proxy_hostname: (null)
** (org.remmina.Remmina:11009): DEBUG: 21:19:51.183: (remmina_rdp_main) - proxy_port: 80
[21:19:51:125] [11009:11189] [INFO][com.freerdp.core] - freerdp_connect:freerdp_set_last_error_ex resetting error state
[21:19:51:125] [11009:11189] [INFO][com.freerdp.client.common.cmdline] - loading channelEx rdpdr
[21:19:51:125] [11009:11189] [INFO][com.freerdp.client.common.cmdline] - loading channelEx rdpsnd
[21:19:51:125] [11009:11189] [INFO][com.freerdp.client.common.cmdline] - loading channelEx cliprdr
[21:19:51:125] [11009:11189] [INFO][com.freerdp.client.common.cmdline] - loading channelEx drdynvc
[21:19:51:126] [11009:11189] [INFO][com.freerdp.core] - freerdp_tcp_is_hostname_resolvable:freerdp_set_last_error_ex resetting error state
[21:19:51:126] [11009:11189] [INFO][com.freerdp.core] - freerdp_tcp_connect:freerdp_set_last_error_ex resetting error state
[21:19:54:179] [11009:11189] [ERROR][com.freerdp.core.transport] - BIO_should_retry returned a system error 32: Broken pipe
[21:19:54:179] [11009:11189] [ERROR][com.freerdp.core] - transport_write:freerdp_set_last_error_ex ERRCONNECT_CONNECT_TRANSPORT_FAILED [0x0002000D]
[21:19:54:184] [11009:11189] [INFO][com.freerdp.core] - freerdp_tcp_is_hostname_resolvable:freerdp_set_last_error_ex resetting error state
[21:19:54:184] [11009:11189] [INFO][com.freerdp.core] - freerdp_tcp_connect:freerdp_set_last_error_ex resetting error state
[21:19:57:251] [11009:11189] [ERROR][com.freerdp.core.transport] - BIO_should_retry returned a system error 32: Broken pipe
[21:19:57:251] [11009:11189] [ERROR][com.freerdp.core] - transport_write:freerdp_set_last_error_ex ERRCONNECT_CONNECT_TRANSPORT_FAILED [0x0002000D]
[21:19:57:251] [11009:11189] [ERROR][com.freerdp.core] - freerdp_post_connect failed
libfreerdp returned code is 0002000D
** (org.remmina.Remmina:11009): DEBUG: 21:19:57.313: [postcommand] (null)
** (org.remmina.Remmina:11009): DEBUG: 21:19:57.313: [postcommand] updated to: 
** (org.remmina.Remmina:11009): DEBUG: 21:19:57.313: (rco_on_disconnect) - Disconnect signal received on RemminaProtocolWidget
** (org.remmina.Remmina:11009): DEBUG: 21:19:57.316: (rco_on_disconnect) - Could not disconnect

Answer 1

For some reason, the docker0 bridge was the reason why I could not RDP to the Windows 10 server. After removing the docker0 interface using sudo ip link delete docker0 I was able to connect.