I just build a new rig today, R9 280x and a fresh driver Adrenaline 18.5.2. Now this happens:
C:\Claymore>NsGpuCNMiner.exe -pow7 1 -xpool ssl://us-east.cryptonight-hub.miningpoolhub.com:20596 -xwal account.worker -xpsw x
╔════════════════════════════════════════════════════════════════╗
║ Claymore's CryptoNote AMD GPU Miner v11.3 ║
╚════════════════════════════════════════════════════════════════╝
XMR: 2 pools are specified
Main Monero pool is us-east.cryptonight-hub.miningpoolhub.com:20596
C:\Claymore>
What might be the reason?
I tested your configuration and it run OK, no problems. Since this is a new build one thing to look out for is Windows Defender deleting 'NsGpuCNMiner.exe', as it usually does, unless added to exeptions.