I tried the demo panel in the link, but it does not seem to give access to changing DNS records on domains. Therefore I cannot see if I can reproduce the problem.
The steps I use are:
- go to domains > mydomain.com
- dns settings > add record
- select TXT for record type
- put 'example._domainKey' in domain field
- put 'p=MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAORlnEC6PRwfG5Cl1n3co9F3tnuUj7vyos7y5C406lnnAeTJTEIAWMTFd2tpjHoshZZSI7P80SclGVejykP8dcsCAwEAAQ==' in record string field
- submit data
- then get; Error: Incorrect DNS Record parameter values were specified. (enter domain name is highlighted as problem)
If _ is removed (example.domainKey) then the record is accepted.
BIND DNS Server is selected in components management.