Emails going missing

I have noticed that quite often emails go missing and dont arrive at their destination. For good example. I sent email just now and it did not arrive at its Gmail destination. I then forwarded the exact same email 2 minutes later to same address and it arrived. The first one still has not arrived. So where is it likely to be ?. Does VM operate a spam filter ????

Thanks

I should add to this post something I just realised. The first email I sent had "test" as subject BUT the body was empty. That one did not arrive. When I forwarded the message it changed the subject AND added a body to message. It seems if email is blank it will not arrive at destination but this therefore must be going somewhere in a filter of VM.

Thanks

VM jut use googlemail now. I tried a blank message with subject test and it threw up a popup asking if I wanted to send a blank mail. I clicked yes and it sent it and it arrived.