I am having this same issue. It says on the bottom when you are not logged in:

"Login to comment"

When I log in, that goes away and "be the first to comment" appears at the top. When you click on it, you are brought to the bottom of the page where there is no form.

I have gone into user groups in k2 and made sure that "post comments" is set to yes.

Any other thoughts on what the problem might be?

Many thanks in advance.

Andy

In case you are using other template than the default ensure that the comment form code does exists in your overrides.

Hi there, I have the exact same problem, using Joomla! 2.5.6, done same as Andy and following your instructions, swapped to Beez5 an Atomic default templates with same results. When setting K2 parameters comments to only for logged users the form dissapears. It's able to see already created comments, but there is no form at all, only a little light blue bar.
Any suggestions?
Thanks in advance!

Hi. Still i cannot reproduce the issue. Just tested under Joomla! 2.5.6 and K2 2.5.7 with no issues. I even turned on caching and still had no issues. Can you provide more information on this? Are you using the latest K2 version? What are your caching settings? Is the system cache plugin enabled? Any other possibly related extensions?

Hi! Thanks for quick response!
In my case cache is off. The K2 is from yesterday download from this web. The System - Cache is disabled. Have no much extensions installed.

Here is a link to an article on my site under development,
develop.itgian.com/loquemegustadeti.es/experiencias/item/3-el-molino-de-palacios
you can use user "test" and passwd "test0000" to take a look.
To make login go to the very top right side at "Accede" menu.

Any info I can provide just ask, thanks a lot!!

Hi. Is the user test in a K2 group with post comments permission?

Hello, yes it is. Is assigned to a group called Usuarios K2 and haves post comments permissions set to yes.