MaraDNS & pfizer.com

[Hrdonka Jan]

  Hello,
would you please advice? I have an urgent problem with one domain (pfizer.com)
I'm not able to solve. The DNS answer is sometimes OK, sometimes wrong, e.g. like this:

root at ns1:/home/hrdonkaj# host -v www.pfizer.com. ns1
Server: ns1.t-mobile.cz
Address: 62.141.0.1
Aliases: ns1

Query about www.pfizer.com. for record types A
Trying www.pfizer.com ...
Query done, 1 answer, status: no error
The following answer is not authoritative:
www.pfizer.com          1751    IN      A       148.168.100.31
root at ns1:/home/hrdonkaj# host -v www.pfizer.com. ns2
Server: ns2.t-mobile.cz
Address: 62.141.0.2

Query about www.pfizer.com. for record types A
Trying www.pfizer.com ...
Query failed, 0 answers, authoritative status: no error
Authority information:
www.pfizer.com          60      IN      SOA     . m.m.m (
                        1       ;serial (version)
                        60      ;refresh period (1 minute)
                        60      ;retry interval (1 minute)
                        60      ;expire time (1 minute)
                        60      ;default ttl (1 minute)
                        )
www.pfizer.com has no A record at ns2.t-mobile.cz (Authoritative answer)
root at ns1:/home/hrdonkaj# 

I though server restart should solve it but it didn't, there's something wrong.
I've discovered that ns3.pfizer.com nameserver doesn't respond and ns4.pfizer.com
is stealth nameserver but I guess none of those should cause problems above.
Anything related to negative cache? I really don't know. Any help or idea will
be appreciated.
  Regards,

  H.
--
Jan Hrdonka