I also have problem with Claymore 10.4. One card (the second one from 2 cards) was lost. Rolled back to Claymore 10.3 and all works.
00:49:22:652 784 ETH: 01/15/18-00:49:22 - New job from eth-eu1.nanopool.org:9999
00:49:22:652 784 target: 0x000000006df37f67 (diff: 10000MH), epoch 163(2.27GB)
00:49:22:653 784 ETH - Total Speed: 63.195 Mh/s, Total Shares: 14, Rejected: 0, Time: 00:42
00:49:22:653 784 ETH: GPU0 31.604 Mh/s, GPU1 31.590 Mh/s
00:49:31:374 1418 GPU 1, GpuMiner cu_k1 failed 30, unknown error
00:49:31:385 1418 GPU 1, GpuMiner kx failed 1
00:49:31:411 e5c NVML: cannot get current temperature, error 999 (an internal driver error occurred)
00:49:31:412 e5c NVML: cannot get fan speed, error 999 (an internal driver error occurred)
00:49:31:389 1418 Set global fail flag, failed GPU1
00:49:31:413 1418 GPU 1 failed
00:49:31:423 8ac GPU 0, GpuMiner cu_k1 failed 30, unknown error
00:49:31:424 8ac GPU 0, GpuMiner kx failed 1
00:49:31:424 8ac Set global fail flag, failed GPU0
00:49:31:425 8ac GPU 0 failed
00:49:31:426 1448 GPU 1, GpuMiner cu_k1 failed 30, unknown error
00:49:31:426 1448 GPU 1, GpuMiner kx failed 1
00:49:31:426 1448 Set global fail flag, failed GPU1
00:49:31:427 1448 GPU 1 failed
00:49:31:428 b9c GPU 0, GpuMiner cu_k1 failed 30, unknown error
00:49:31:428 b9c GPU 0, GpuMiner kx failed 1
00:49:31:428 b9c Set global fail flag, failed GPU0
00:49:31:429 b9c GPU 0 failed
00:49:31:462 e5c NVML: cannot get current temperature, error 999 (an internal driver error occurred)
00:49:31:463 e5c NVML: cannot get fan speed, error 999 (an internal driver error occurred)
00:49:32:423 784 ETH: checking pool connection...
00:49:32:423 784 send: {"worker": "", "jsonrpc": "2.0", "params": [], "id": 3, "method": "eth_getWork"}
00:49:32:488 784 got 243 bytes
00:49:32:488 784 buf: {"jsonrpc":"2.0","id":0,"result":["0x04892af762b7ee2c71eea61298f6944f89b91fa4117a84bb26b9cedd1ebc219e","0xec6e8e0d8056cf9eb61046eaeb754b8e71f48e10a86c61f4d287b4ac5244653f","0x000000006df37f675ef6eadf5ab9a2072d44268d97df837e6748956e5c6c2116"]}
00:49:32:488 784 parse packet: 242
00:49:32:488 784 ETH: job is the same
00:49:32:488 784 new buf size: 0
00:49:33:510 784 got 243 bytes
00:49:33:510 784 buf: {"jsonrpc":"2.0","id":0,"result":["0x07892f73c1f7a658fc5a32b4cfad2fc48bb4d192b965dfde29504609b54bcb7f","0xec6e8e0d8056cf9eb61046eaeb754b8e71f48e10a86c61f4d287b4ac5244653f","0x000000006df37f675ef6eadf5ab9a2072d44268d97df837e6748956e5c6c2116"]}
00:49:33:510 784 parse packet: 242
00:49:33:510 784 ETH: job changed
00:49:33:510 784 new buf size: 0
00:49:33:510 784 ETH: 01/15/18-00:49:33 - New job from eth-eu1.nanopool.org:9999
00:49:33:510 784 target: 0x000000006df37f67 (diff: 10000MH), epoch 163(2.27GB)
00:49:33:511 784 ETH - Total Speed: 0.000 Mh/s, Total Shares: 14, Rejected: 0, Time: 00:42
00:49:33:511 784 ETH: GPU0 0.000 Mh/s, GPU1 0.000 Mh/s
00:49:34:096 1430 em hbt: 0, fm hbt: 31,
00:49:34:096 1430 watchdog - thread 0 (gpu0), hb time 4555
00:49:34:096 1430 watchdog - thread 1 (gpu0), hb time 4680
00:49:34:096 1430 watchdog - thread 2 (gpu1), hb time 6755
00:49:34:096 1430 watchdog - thread 3 (gpu1), hb time 6880
00:49:34:096 1430 WATCHDOG: GPU error, you need to restart miner :(
00:49:34:146 1430 NVML: cannot get current temperature, error 999 (an internal driver error occurred)
00:49:34:146 1430 NVML: cannot get fan speed, error 999 (an internal driver error occurred)
00:49:34:196 1430 NVML: cannot get current temperature, error 999 (an internal driver error occurred)
00:49:34:196 1430 NVML: cannot get fan speed, error 999 (an internal driver error occurred)
00:49:34:513 e5c NVML: cannot get current temperature, error 999 (an internal driver error occurred)
00:49:34:513 e5c NVML: cannot get fan speed, error 999 (an internal driver error occurred)
00:49:34:564 e5c NVML: cannot get current temperature, error 999 (an internal driver error occurred)
00:49:34:565 e5c NVML: cannot get fan speed, error 999 (an internal driver error occurred)
00:49:34:615 e5c NVML: cannot get current temperature, error 999 (an internal driver error occurred)
00:49:34:615 e5c NVML: cannot get fan speed, error 999 (an internal driver error occurred)
00:49:34:666 e5c NVML: cannot get current temperature, error 999 (an internal driver error occurred)
00:49:34:666 e5c NVML: cannot get fan speed, error 999 (an internal driver error occurred)
00:49:34:667 e5c GPU0 t=0C fan=0%, GPU1 t=0C fan=0%
00:49:35:398 1430 Restarting OK, exit...
Both cards are ASUS ROG STRIX GTX-1070 GAMING O8G