Hi!

First time when I activated my K2 Content module the title was showing OK, but after I have activated other modules, the title of my K2 Content Module disappeared, even though it still configured to be Show... Why?

And also, Bootstrap size option doesn't work. I put 2 for the option of Bootstrap size to get two columns, but it didn't work out.. out do I do wrong?

Its hard to say.

Can you provide a link to the page?

It's on my localhost...

the strange thing is that, not only K2 Content Module title doesn't appear, also Joomla Menu module title doesn't appear... I"m using J3

Check what H tag that is, and see if maybe there isn't a css of hidden applied.
Display:none;

Hi
I have same problem bootstrap module size no work.

Were you able to solve it already?

Regards

No,
still didn't solve, if you solve post a solution please

Does it show in the HTML source?
If yes, then its a matter of a CSS issue.
If no, then it can be a problem with the module template.