Searching this error it seems it could be many things.
Either wrong credentials or a wrong region (different than the one for your key-pair).
It could also be that your computer clock is wrong (see example https://github.com/mitchellh/vagrant-aws/issues/372#issuecomment-87429450 ).
I suggest you search it online and see if it solves the issue, I think it requires some debugging on your end.