Why can not I add a comment to YouTube?
I think the problem is that you do not have access to YouTube, there is something that automatically knocks out this hosting and it becomes a problem when writing a comment, check your account and if it does not help then just go to the channel.
Many browsers automatically block pop-up messages, because pop-up advertising works on the same principle. You need to add Youtube to the exception sites. For example, in Google Chrome, you need to click on the icon at the top and allow pop-ups for this site.
I also ran into this, and it's all about the plugin. It is necessary to remove or disable the plug-in, which has a little dog on the icon .. This is a type of ad blocker, it does not redirect to the comment. Instead, he put ADBlock, which is almost worse and probably even better blocks everything and starts commenting. Now everything is all right.
The main reason that you could not leave comments on YouTube is that you went to the site as a non-registered user, and those who have their own account on Google can leave comments.
Also try logging in from a different browser.
You are not logged into your Google account. I had a similar experience, cleaning and restarting the computer helped, then - logging into the account. Now another problem - when trying to write a comment, they write that I cannot leave it. The reason is clear - I was blocked on the channel, since I can leave comments on other channels.
Only registered users can comment on Youtube. That is, you need to go to the site of the social network Google+ and register in it. The browser you are using is quite rare, possibly not fully compatible with Google services. Perhaps, because of this, the invitation to register is displayed unstably. Try registering with another browser.
and to me disconnection NetFilterPRO helped, adblok left, and all the rules, comments I can leave on YouTube
The reasons for the fact that the user does not have the opportunity and can not add comments, there may be several.
First, it is worthwhile to know that comments on Youtube are only available to those users who have a Google+ profile.
Secondly, check that the cookies are enabled in the Chrome settings.
Thirdly, in the browser settings can be a blocking from pop-up windows, check.