
Symptoms:
Whenever we try to access Web Dispatcher admin page it does not work and we only get default .html blank page.
Below is the syntax to web dispatcher admin page:
http://<hostname>:<port>/sap/wdisp/admin/public/default.html.

Cause:
Problem is probably caused by programming error or the outdated Kernel patch
Solution:
Apply the latest kernel patch or apply referenced Kernel patches as per the updated SAP NOTE 2215780.
Workaround:
Instead of using default web dispatcher admin URL use below URL with welcome.html:
http://<hostname>:<port>/sap/wdisp/admin/public/welcome.html