The problem with co-op (Dark Souls 3)

In General. My friend can't play together. He sees my signs, I don't see it. It happens that we see each other's signs, but can not call(says that it is impossible to call). The only caveat in all this is that I'm playing on ng+, and the other just on ng. Can be this the problem? But on the other side on ng+ I saw his characters as he is mine, but could not hold, while the rest can easily call him and me(casual players)