Error "Can't open display: localhost:x.y" When Running xclock on Xming

The Problem

Unable to do Display Setting for Xming. You get the error below while trying to run Xclock on server for non-root user , e.g. ‘oracle’:

$ xclock
Xlib: connection to "localhost:10.0" refused by server
Xlib: PuTTY X11 proxy: MIT-MAGIC-COOKIE-1 data did not match
Error: Can't open display: localhost:10.0

The Solution

Incorrect authorization information configuration was present on the X server. Follow the steps outlined below to resolve the issue:

1. Login as the root user

2. Type ‘xauth list’ to get authorization entries:

# xauth list
12-322-11-11/unix:10 MIT-MAGIC-COOKIE-1 cf4967d5a6c0e6d5f33285a3343dfdce

3. switch to the user:

# su - oracle

4. Add entire output using “xauth add” command:

$ xauth add "12-322-11-11/unix:10 MIT-MAGIC-COOKIE-1 cf4967d5a6c0e6d5f33285a3343dfdce"

5. start xclock again

$ xclock