Milter-greylist

I´m using milter with spamd, and i have this:

spamdsock unix "/var/run/spamd.sock"
dacl blacklist spamd > 15 msg "Message blocked for spam content"
dacl greylist spamd > 10 delay 4h msg "Message greylist for spam content"
dacl greylist spamd > 6 delay 2h msg "Message greylist for spam content"

If i have a problem with spamd or i stop it the milter brokes there, here an example:

LOG
milter-greylist: spamd connect failed: No such file or directory
milter-greylist: ACL evaluation failure

And Postfix returns this:
...4.7.1 Service unavailable - try again later..

i´m doing something bad here? or is this the way is suppose to work.

best regards