Running xterm over SSH with a DISPLAY parameter correctly set can show an error for the Drawable.
# xterm X Error of failed request: BadDrawable (invalid Pixmap or Window parameter) Major opcode of failed request: 55 (X_CreateGC) Resource id in failed request: 0x5a Serial number of failed request: 3 Current serial number in output stream: 4
To solve it add or uncoment in ssh_config
ForwardX11 yes ForwardX11Trusted yes
And restart the SSHD service.