Kitten isn't allowed to come inside

My kitten won't come inside. There is something that won't allow my kitten to come inside. I just added the kitten to my household, but my older cat has no problem coming in. My kitten is currently on the sidewalk, but when I try to call her inside, a bubble pops up saying that there is something in her way, but there is nothing I can think of besides the door, which is unlocked.