Tried to identify the problem...no results...
changed the research...nope
deleted all barb city (assuming it might be the spawning Archeron)...nope
no one is building anything special, no great wars or anything...
any ideas?
The Sheaim want to build on a mana node in the south east of their territory but there's a barbarian bear in the way. Remove the bear and you should be able to continue.