We have checked your database and seen all invitations was sent to facebook through facebook API, we think the problem belong to your facebook app which was be seen as spam appication.

P/s: You should check invitation (message) on both inbox and other (spam messages).

i dont know how to get it through there heads 
i keep saying over and over that the problem is in there plugin 
one answer was my server with 4 cpu s and 4 gb ram was to slow to run there plugin 
i am now on 8 cpu s and 8 gb ram i hope thats not to slow for there plugin lol

how many times have i got to say this 

PLEASE READ WHAT I AM SAYING AND STOP GIVE SHIT ANSWERS

invites work if you manual select friends to invite

manual select 5 friends click Send it works
manual select 20 friends click send it works

IT DOES NOT WORK IF YOU SELECT ALL AND CLICK SEND
THE AUTO SEND PER DAY DOES NOT WORK
THE PLUGIN IS SET TO SHOW 300 FRIENDS PER PAGE AND SEND 20 INVITES PER DAY

BUT IT DOES NOT WORK

I WILL SAY IT AGAIN IT DOES NOT WORK

IT HAS NOT WORKED FROM DAY ONE
IT IS NOT A CRON PROBLEM
IT IS NOT BECAUSE THE SERVER IS SLOW
ITS BECAUSE THE SHIT PLUGIN DOES NOT WORK
ALMOST 12 MONTHS NOW

DID YOU GET IT THIS TIME THE PLUGIN DOES NOT WORK
I DONT WANT ANY MORE BULLSHIT EXCUSES I WANT THE THING WORKING