Recently, Remmina RDP fails with this error message (see below screenshot). This may have something to do with FreeRDP, I guess. (And yes, I did explicitly install the FreeRDP bundle. Could it be that Remmina is actually looking for the older FreeRDP 2.x?)
Any thoughts, @arjan?
FreeRDP has been a bit of a pain for us lately – someone asked us to update to the latest (which makes sense from security angle etc)… but it greatly broke compatibility including with Remmina which is hosted in the FreeRDP github so it even broke itself to some extend
We’ll track to see how this develops and hope to get this fixed asap but somehow this part of the world is a bit of a mess
Yeah, that someone was me. 
So, here’s what Remmina devs say about this: Remmina no longer loading RDP protocol plugin (#3071) · Issues · Remmina / Remmina · GitLab
Oddly, this issue did not arise for me until 43250, even though I had been running swupd’s packaged Remmina every day.
The flatpak seems to work instead.
They must have fixed it in the meantime (i.e. since Feb. 2024), but it looks like it’s broken again in CL43250.
As for the Flatpak version, that doesn’t work with hostnames, so you’ll have to type in the IP address. See also this, and this.
(Or maybe there’s a Remmina plugin that needs to be installed to make it work with hostnames? 
)
I am using IP addresses. 
Recently, RDP in Remmina also stopped working for me:
Failed to load plugin: /usr/lib64/remmina/plugins/remmina-plugin-rdp.so.
Error: /usr/lib64/remmina/plugins/remmina-plugin-rdp.so: undefined symbol: freerdp_settings_set_monitor_def_array_sorted
I installed Flatpak version and copied the rdp plugin from there to ~/.config/remmina/plugins/remmina-plugin-rdp.so And it works fine.
remmina -V:
RDP plugin: 1.4.40 (Git n/a), Compiled with libfreerdp 3.15.0 (3.15.0), Running with libfreerdp 3.14.1 (rev n/a), H.264 No