How to send mails?
 

The SendMail() command doesn't work within my addon. Is there any kinde of parameter I have to pay attantion? or are there any special conditons that have to be meet.
EVENT_MANAGER:RegisterForEvent(self.name, EVENT_ACTIVITY_FINDER_ACTIVITY_COMPLETE,self.ActivityEnd)


function TestAddOn.ActivityEnd()
SendMail("@someon", "Titel", text_to_send)
end

text_to_send is just some text

Well, text_to_send is variable, but your function didn't specify it. Sure, it can be global for your addon variable, specified at Init - I dunno.

Even if i send some text like "hi" it diden't work

i have the solution you need to call RequestOpenMailbox() befor and CloseMailbox() after SendMail

it really works? Need to try