Some ccTLDs like .DE and .FR have restrictions on the maximum number of name servers that can be used in their registrations. If there is a limit then typically it will be either 4 or 5 as a maximum. However some UltraDNS customers will use six authoritative name server hostnames (pdns1-6). Either entering all six into the registration OR limiting the number in registration and DENIC/FRNIC running a check on the zone file will return vague errors such as:
Error: Nameserver error. (ERROR: 118 Inconsistent set of NS RRs (IP, NS host names) (/2610:a1:1016:0:0:0:0:1, [pdns1.ultradns.net, pdns6.ultradns.co.uk, pdns2.ultradns.net, pdns5.ultradns.info, pdns3.ultradns.org, pdns4.ultradns.org]) /Code: 319)
Once the zone is created in the Ultra portal two of the name server records should be removed (typically pdns5 and pdns6). Then input the remaining Ultra name server hosts into the registration. This should correct the errors seen previously.