Do you have any net or conditional or other rules set?
You may have to allow the vias under those settings also.
I seem to remember that you might have trouble manually inserting a via if there is more than one via type defined. Start a dummy route, right click and select the via type you want. You should be able to insert it now.
Thank you to both posters for help!
I really feel silly now, totally forgot that anytime drill pairs are set up with a partial pair you MUST also set up a Top & Bottom pair.
I looked at that menu a number of times and it just didn't click.
I finally spotted the error message that pops up quickly when placign a via which led me to pair set up menu one more time
which is when that huge light bulb went off in my head.