​​​​​​If you are encountering the URL No Longer Exists issue when setting up the CTI integration try the following steps to help resolve and redirect the window URL. 

In SalesForce settings, as a SF admin, go to the visualforce pages page:

Look for an item called “OpenCTIIndex”, you want the one without any numbers:

Next to the “Security” on the OpenCTIIndex item, there’s a preview icon, please click on that to open up the visualforce page in preview:

That should open our CTI app in a new tab, although it might not be in a logged-in state:

You may notice the url of this new tab change for a few times before the app loads up. But usually within a few seconds it will stop changing and our app will be loaded. At this time, you can copy the URL.

Now back to the SF settings and in Call Centers, find our call center definition and edit it. Then replace the CTI Adapter URL with the URl you’ve just copied:

Save that, then make sure that the visual force preview tab is closed.

Now, reload the CTI app and test again.

SalesForce over the years has gone through some changes in how their domain names are used for different features. It’s something that we can’t control and often will require customers to go through these steps to make sure that the adapter URL is pointing to the correct domain. Otherwise, the CTI app could not communicate with the SF app through their OpenCTI sdk. This is the number one culprit to click to dial not working from our years of support cases data.