Enemy dominion too high for me?

[Finalgenesis]

Preachers preaching on top of a temple get +1 level in preaching effectiveness I believe.

Part of the reason for your problem could be that enemy dom is coming out enmass (especially if he's in a corner, or just have a well-consolidated empire), especially if the province in question is geographically a focal point.

Playing lots of water nations I hit on this problem a lot as narrow water strips are almost all focal points to dom spread, I've had 20 lvl 2 priest (lvl 3 with temple) preaching in a focal water without raising dom at all, but then there are probably 10+ enemy dom pushing into it every turn