Help with You Tube Comments account

HI, I have manager rights on a couple of clients Youtube accounts, the only one that wishes to use the live comments display and moderation from within mimLive does not appear in the dropdown list at the time I go to add this channel in social media preferences. I have been through the settings on several accounts and can not find a difference between them to ttell me why this does not appear.

I will ask Google the same question but hold little hope of help there.
Im in desperate need to have this working so any suggestions will be greatly appreciated.