I was having the same exact issue with "this server is temporarily unreachable" for all my logging servers, but on a Nexus 9372 version 7.0(3)I2(2d) I had to hit ctrl+z after each logging server command instead of enter. How did anyone figure that on...

I had this same problem. The solution was to upgrade ASA platform to ASA 5516-X. I know it's not desirable to have to buy new hardware, but it is necessary for PCI compliance, so our higher ups signed off on the purchase immediately.