Nagios Support Forum

Awesome, good to know it's working now, may be you can share the root cause and the solution just in case someone else experiencing similar problem.

May I suggest 2 things:

1. Does email sending from cli works? Better test it the same way you call it from Nagios command definition by supplying dummy strings to replace the Nagios variables
2. Enable debugging in nagios.cfg

and see how it goes from there?