Question

Why i could not accept your invitation summary

Answer 1

Sometimes people can't accept things like invitations. I cannot accept your invation because, I don't really know you. Most people are nice and you seem nice but I'm not sure, if I should accept your invitation. It's hard for me to accept an invitation when I don't really know someone like you. 

I don't know if this is what you wanted but you can add on to it.