This is what it looks like connecting to a F38 system when remote desktop is working fine:
** (gnome-connections:2): DEBUG: 15:08:30.954: connection.vala:159: No credentials found in keyring. Prompting user.
** (gnome-connections:2): DEBUG: 15:08:41.549: Connecting to 192.168.0.110…
[15:08:41:325] [2:54] [WARN][com.freerdp.crypto] - Certificate verification failure 'self-signed certificate (18)' at stack position 0
[15:08:41:325] [2:54] [WARN][com.freerdp.crypto] - CN = GNOME, C = US
[15:08:41:326] [2:54] [ERROR][com.freerdp.crypto] - @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
[15:08:41:326] [2:54] [ERROR][com.freerdp.crypto] - @ WARNING: CERTIFICATE NAME MISMATCH! @
[15:08:41:326] [2:54] [ERROR][com.freerdp.crypto] - @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
[15:08:41:326] [2:54] [ERROR][com.freerdp.crypto] - The hostname used for this connection (192.168.0.110:3389)
[15:08:41:326] [2:54] [ERROR][com.freerdp.crypto] - does not match the name given in the certificate:
[15:08:41:326] [2:54] [ERROR][com.freerdp.crypto] - Common Name (CN):
[15:08:41:326] [2:54] [ERROR][com.freerdp.crypto] - GNOME
[15:08:41:326] [2:54] [ERROR][com.freerdp.crypto] - A valid certificate for the wrong name should NOT be trusted!
[15:08:41:326] [2:54] [WARN][com.freerdp.crypto] - The VerifyCertificate callback is deprecated, migrate your application to VerifyCertificateEx
[15:08:42:530] [2:54] [INFO][com.freerdp.gdi] - Local framebuffer format PIXEL_FORMAT_BGRA32
[15:08:42:530] [2:54] [INFO][com.freerdp.gdi] - Remote framebuffer format PIXEL_FORMAT_BGRA32
[15:08:42:533] [2:54] [INFO][com.freerdp.channels.rdpsnd.client] - [static] Loaded fake backend for rdpsnd
[15:08:42:533] [2:54] [INFO][com.freerdp.channels.drdynvc.client] - Loading Dynamic Virtual Channel disp
[15:08:42:534] [2:54] [INFO][com.freerdp.channels.drdynvc.client] - Loading Dynamic Virtual Channel rdpgfx
** (gnome-connections:2): DEBUG: 15:08:42.936: Connection established