In order to use Comment Likes(UPVOTES) Service you need to use a different type of link;

https://www.youtube.com/watch?v=L9zyNmMNHtQ&lc=UgxjHKnslwLiDuxND2N4AaABAg

to get this link you need click on the time icon next to your comment in the comments section, if you are using it on a new comment that you just wrote, it would say "Just Now" or if it has been written more than a minute ago it would say the related time right next to your name on YouTube.

make sure that the link you copied from the search bar after clicking the time icon includes v="video link" and lc="comment link"