OSPF Problem

Two of my routers remain in ExStart state and never pass to full state in the ethernet interfase that link them. all the other interfases work ok.
Anyone has experience this problem, or know how to solve this?

Firewall?

OSPF settings?

Problem solved. The fact was that the MTU for the to ethernet interfases was different (one 1500 the other 1488). Changing the MTU solve my problem.