Why can't I respond to any of the questions? The format won't let me post.?

I'm having trouble too. It's not functioning correctly for me. I'm hoping they'll get it straightened out

It would help to know what type of device you're using (since you mention the new format) and what browser. I'm on desktop PC using Chrome browser and have no issue answering questions in the new format, although I dislike the format so have been accessing questions though the portal for Canada, via which I can access the old format.

In the new format (desktop) you should see a button directly below the question that says "+Answer". Click that and a text box will open for you to type your answer where it says "Write your answer here" and then click the submit button at the bottom right, beneath the source box and the checkbox where you can check to get notifications of new answers to that question.

My suggestion would be to try a different browser or device, or add "ca." before 'answers.yahoo.com...." in the URL to see if it works better for you under the old format.

There is a glitch with the Submit button. Refresh the page and try again. You also will not be able to post if you have reached your daily limit or you try to put a percentage sign in your posts, and you will not be able to answer questions if an asker has you blocked.