It happened after upgrading Zabbix server to ver 2.0.3:
I'm creating some item...
Then I'm trying to create a trigger for it:
...and get failure:
It says that item key is incorrect but it seems not to be true. I already have item with similar key (created via UI):
..and I CAN add triggers to this existing item.
Also note that I can find item with "incorrect" key by its key:
the host seems to be correct:
Here is a comment from https://www.zabbix.com/forum/showthread.php?t=39007
Judging by the ID of the item you've created, it belongs to a different node then the host. You shouldn't be able to create such items at all. It probably has something to do your node configuration.