User-Agent:       Mozilla/5.0 (X11; Linux x86_64; rv:128.0) Gecko/20100101
Firefox/128.0
Build Identifier: 

When starting an X application at the command line, I am getting an error
message about "MIT-MAGIC-COOKIE-1".

Here's an example:

% xterm
Warning: Tried to connect to session manager, Authentication Rejected, reason :
MIT-MAGIC-COOKIE-1 authentication rejected

However, the application does start.

I've tried this on another computer, where all is fine.  I'm not sure what is
special about this system, other than it is using an NVME disk.

I am using KDE Plasma 5, and I use SDDM as display manager

Reproducible: Always