I've clealy missed something fundamental, but i can't find it anywhere.
My old 3.2 installation works perfectly, sends email alerts when error or performance thresholds are exceeded, or interfaces go up or down.
I've installed 4.2 on a new server, it is collecting configurations, hardware inventories etc. and will email me reports of those quite happily. It log alerts in its local database and I can log in and manage them.
It will NOT send me an email telling me an interface has gone up/down, or exceeded the performance thresholds (set at the same as 3.2)
I've had to leave 3.2 running until this is resolved, now there's no DFM page I'm going through every one of the pages one by one and I can't see anything I've missed.