I had a issue with PhoenixMiner 5.1c
My Rig is:
CPU: G3930
RAM:; 16GB DDR4
HDD SSD240GB
GPU: 7x RX570 4GB
POOL: Coinotron


IMPORTANT! All owners of AMD cards with 4 GB RAM must upgrade to PhoenixMiner 5.2b or later version to continue mining after DAG epoch 373 (set -daglim 1, or see bellow how to use the -daglim option; you also need to add -dagrestart 1 to allow maxium possible value of -daglim). Additionally, here are some important tips for longest possible usage of 4 GB AMD cards with PhoenixMiner 5.2a and later:
Issue: yesterday my rig making 175Mhash now today cannot start the miner, still 0mhash and says thread not responding.
Im use drivers AMD 27.20.12029.1000.

Regards!