If a data element is missing a trailing dot then less-than-helpful error message may result:

ipa dnsrecord-add --ptr-rec=server.example.com. 1.168.192.in-addr.arpa 1
ipa: ERROR: invalid 'cn': IP address must have exactly 4 components

It was missing the trailing .

Before:
ipa dnsrecord-add --ptr-rec=server.example.com. 1.168.192.in-addr.arpa 1
After:
ipa dnsrecord-add --ptr-rec=server.example.com. 1.168.192.in-addr.arpa. 1