Non-latin names in ISPConfig are not fully supported.
In ISPConfig 3.0.3.2 here: /usr/local/ispconfig/interface/web/dns/form/dns_slave.tform.php
this line: 'regex' => '/^[\w.-/]{2,255}.[a-zA-Z]{2,10}[.]{0,1}$/',
misses: "0-9-"
should be: 'regex' => '/^[\w.-/]{2,255}.[a-zA-Z0-9-]{2,10}[.]{0,1}$/',
Please note that I haven't performed a complete check, possibly there are other places where this is also true.