Verify the authentication type and authentication key specified for the appropriate interfaces on this and the source router. The types and keys must match in order for authentication to succeed. If MD5 authentication is being used and OMPROUTE is stopped or recycled, ensure that it stays down for at least 3 times the largest configured dead router interval of the OSPF interfaces that use MD5 authenticaiton, in order to age out the authentication sequence numbers on routers that did not recycle.