I believe it's a known issue, I've seen several complaints about it here recently. Did you also search the ticket system: support.freenas.org ?? Sometimes looking at tickets, even closed ones, can give you a clue there's a problem.
Sometimes searching the forums using google instead of the forums search features gives better results, like this for example:
email "no route to host" site:forums.freenas.org
I understand the way things get fixed and break again with FreeNAS can be quite frustrating sometimes. ;)