In wordpress, after updating W3 Total Cache plugin to the latest version you may get this error in CDN configuration.
” A configuration issue prevents CDN from working: The “Authorization key” field cannot be empty. You need to select / create a pull zone. ”
check the screen shot below.
To Solve this issue
On the error message click Specify it here or select CDN from w3tc menu and move to configuration part. Check the screen shot
Now click on the Authorize button, you will be redirected to NetDNA CDN site.
Login using your MaxCDN Account. Once logged-in, you will get your Authorization key.
Copy that key and paste it in Authorization key field under CDN configuration in W3TC. Check the key whether its working or not by clicking on the Test NetDNA button.
That’s it save the settings.
Hope this will be helpful for you!!!