Normally this happens when the YouTube account you connected on SocialBook is not the one you currently logged in on YouTube:

To fix this, please follow the following steps:

Step 1:

First make sure you have SocialBook Builder installed: https://socialbook.io/help/socialbook-youtube-builder-manual/

Step 2:

Go to https://socialbook.io/connect_socialmedia and make note of the channel you connected:

Step 3:

Now go to https://www.youtube.com, click on the top right corner your avatar, and make sure the one you logged in is the same channel as the one you connected on SocialBook:

Step 4:

If they do not match, you can switch to the connected  channel from YouTube:

Once the channel matches, you should see the loading button on the right side:

and you can click to see the video stats now.