Hmm, this seems to be the same problem as here: Adding extra domain doesn’t work, except that rebooting doesn’t help.
syslog is full of:
Aug 30 16:42:24 box named[11994]: error (connection refused) resolving 'box.fuess.nl/A/IN': 149.210.177.248#53
Aug 30 16:42:24 box named[11994]: error (connection refused) resolving 'box.fuess.nl/A/IN': 149.210.178.61#53
Aug 30 16:42:24 box named[11994]: error (connection refused) resolving 'fuess.nl/NS/IN': 149.210.177.248#53
Aug 30 16:42:24 box named[11994]: error (connection refused) resolving 'fuess.nl/NS/IN': 149.210.178.61#53
for the domains I’m managing.
Looks like named and nsd are conflicting again. What to do? I would really like mailinabox running smooth again 
some extra info:
$ sudo lsof -i :53
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
named 11994 bind 20u IPv4 34681 0t0 TCP localhost:domain (LISTEN)
named 11994 bind 512u IPv4 34680 0t0 UDP localhost:domain
nginx 21879 www-data 10u IPv4 47205 0t0 UDP box.fuess.nl:48809->google-public-dns-a.google.com:domain
=======
$ sudo netstat -tulpn | grep :53
tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN 11994/named
udp 0 0 127.0.0.1:53 0.0.0.0:* 11994/named
=======
$ sudo netstat -tulpn
gives no mentions of nsd running.
sudo service nsd stop
results in:
stop: Unknown instance:
Stopping bind9 and then starting nsd results in (in syslog):
Aug 30 16:57:09 box nsd[22217]: can't bind udp socket: Invalid argument
Aug 30 16:57:09 box nsd[22217]: server initialization failed, nsd could not be started
Any help is greatly appreciated!