i was in contact with steam support about this and they indicated that its a network issue of some sort
they suggested the following things to try
- Refresh your local network
- Change your download region
- Investigate various anti-virus software
- Investigate other programs and services
- Test your online connection
i did all of those with no immediate effect.
i also open up the ports suggested in their
help page
without immediate success.
then on a whim i tried using a vpn real quick (tunnelbear in my case) and it verified instantly and let me play
i cant disregard the other steps i took incase its a non-immediate effect but it sure worked once i had the vpn up and going.
tldr: network issue. try using a vpn to verify the last bit