zone xfer failing

[List User]

i have found that one of our internal zones has not xfered in about a
week.  the slaves are logging 
 not authoritative for mydomain.com, SOA query got rcode 0, aa 0, ancount
1,aucount 0

and 

 zone mydomain.com/IN: refresh: non-authoritative answer from master
10.10.1.1#53

this points to an error on the master usually but i can't seem to find
anything.

i did a dig off of all ther servers and the only one to show an NS record
for mydomain.com is the master

dig ns mydomain.com @mylave01
---no ns records back
dig ns mydomain.com @myslave02
--no ns records back
dig ns mydomain.com @masterserver
good ns records come back

i reloaded the master and the slaves.  nothing but the errors above.
anyone have a clue?  i definitly see the ns record for mydomain.com in the
zone file and when i do digs off the master.

thanks