Replistor for Exchange 2003 Sync Needed

I have set up a failover server for our Exchange 2003 environment. It appears to be replicating all of the files without trouble.

However, the specifications all say "SYNC NEEDED" and I set each to Sync, but they have not made any progress in several days. Meanwhile, log files, .edb files, etc. are all being replicated.

What did I miss?