Click "Update Permission". A popup will show you what to do in the next screen. Click "Next" to continue.
On the next screen, click on the "Continue" button to grant all the requested permissions to all pages. If some permissions are missed you will continue with Step 4... If all the required permissions are already greanted you'll be redirect back to the connect screen.
Or click "Choose what you allow" and find your missing page on the full list of pages. Make sure to tick the checkbox next to this page.
Still don't see your page? Check out this helpdoc for possible reasons.
Make sure ALL permissions are enabled. Then click "Continue".