Hello can u help me ? my K2 error cz user cant to add new item . . .
Please help me and thanks before

Hello,

Does this user have permission to add items? Does this problem occur when trying to add a new item in the frontend or the backend?

I've done it smua, but still can not, can you help me? I will send my website username and password, thanks

Make sure that your user is assigned to the correct user group and that that user group has permissions to add items.
Also make sure that Frontend Editing option is Enabled. (Check in K2 > Parameters > Frontend Editing the option "Enable frontend editing").