Please try the following if you click to Gather CTR Data and nothing happens at all on YouTube's site...
1. Make sure you have the TubeBuddy browser extension installed. Head to https://www.tubebuddy.com and click the "Install" button.
2. If your video is getting fewer than 5 Views per day, it might simply be the case that there is no data to gather because YouTube limits data displayed in certain cases like this. Check back the next day or make sure to run tests on videos that are getting more views.
3. Try setting up the test in a different browser (Chrome/MS Edge).
4. Sometimes signing out of Google and then signing back in with a single account, can fix gathering issues.
5. If you’re a channel manager, reach out to the channel owner to reauthenticate the channel by re-linking it from their Account Page to refresh the data.
6. Try setting up the test in YouTube Studio as opposed to our web portal (go to YT Studio > Content > select a video > and select Test Alternates at the top of the page):
Still having issues? Submit a support ticket from our Help Center and we'll help work through the issue (which might involve temporarily needing access to your channel).