I thought you had it email working?
It's working 100%
If you change 'conditions' to:
conditions=alarm,mode,parameter
Then you should get an email whenever the boiler starts/stops and when you change any parameter so it's easier to test that it is working.
Do you get any errors in the event list when it tries to send an email?
I think that possibly the 'from' setting should look like an email address, I have 'from=user@mail.com' in my conf and that works with gmail. Google rewrites the 'from' field to match the account you are logged in to anyway, but it might possibly be rejected if it's not an email address at all.
And did you activate 'allow less secure apps' in your gmail settings? It does not work without that.