I played Dark souls 3 quit the game went to have a dinner started playing again and I have not earned any silver after 2 hours of play and then this pooped up... https://imgur.com/a/7Gl6W
So here's the things i try to figure out when the Cortex is not working for me. First check if your amount of silvers have been or not added the amount of the silvers earned by the previous gaming session, because it may not always give you the "earning the silvers" screen whenever you enter a game or when you exit, both on Cortex and on zVault. Those typical things like a restart, or a reinstall of the Cortex could be a way. Other than that, this is a problem from the Cortex itself, which usually take a couple of hours until it's repaired as far as i noticed. Have an update or reupdate if you can and if nothing of this help, i guess you simply have to wait for itself to be fixed.
The thing that seemed that happened is that this problem just afect some people and just "now" on the afternoon
There are times which (i think) the support is making some changes in the Cortex especially for problems like yours, so in order for that to be applied some Cortex functions are stopped i presume, and this is why for some unknown periods earning is unavailable and i said that it could be restored in a few hours. This is just one of my beliefs dosen't mean it's true, but it's my way to explain why Cortex does not work properly.
Same did some restarts, re-installs, only managed to earn a little bit then after a few hours on a different game i received none, checked cortex my games has no earn rates which is weird.