there was a mod version mismatch after last update of Structures Plus. all mods on each map freshly reloaded.. back to normal now!
If the message still on your screen, delete also your ark mods at \\Steam\steamapps\common\ARK\ShooterGame\Content\Mods (except folder: 111111111, Ragnarok, TheCenter; except file: 111111111.mod) and reload it by joining server again.