You may feel very annoying because this error keeps coming repeatedly.
So even you are the victim of this error and want to get rid of it as soon as possible, you can go through various steps listed below in order to fix windows phone error 80073cf9.
I hope your DB is in Documents folder rather than in application bundle file.
I just got a new router and whenever I try to download that exact message pops up (with the game title) The download starts, goes up to about 5 mbps for about thirty seconds and then stops with that message popping up.
I've deleted my steam folder, and tried everything I could find but nothing has worked.. It would help if you listed the brand of your new router, and its model number.
Some routers trigger a cut off of all internet downloading when IP flooding is triggered when enabled. First in port forwarding, give the service a name for each set of UDP or TCP port ranges setup. It will ask you to enter an IP address of the machine running steam, the IP address the router gave your computer.
As it considers it as an attack from an outside source or from a Wan, in other words the update or download from the steam server ok. You can find this i your router under the connected devices section, where it lists the name of the computer and the IP address the router assigned it.