use distribution exec sp_browsereplcmds @xact_seqno_start = '0x<first 20 bytes of Transaction sequence number>', @xact_seqno_end = '0x<first 20 bytes of Transaction sequence number>'But when the replication has been down for quite a while it's impossible to see what caused the problem in SQL. Allthough it wasn't the first thing that came to my mind, it can be found in the event log:
Hopefully this helps.