Check if your nvidia drivers are correctly installed.

My settings for nvidia are:
PhoenixMiner.exe -nvidia -coin eth -pool ssl://eu1.ethermine.org:5555 -pool2 ssl://us1.ethermine.org:5555 -wal wallet.Rig001 -proto 3

Haven´t included the the settings for OC as it depends on your videocard.

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Drivers are ok, as I said I am using Phoenix Miner after Claymore ended and still using him on severals rigs with v5.8x without anny issue and for updates I just copied old bat file into directory of new version but since v5.9 it is not working like that. In this moment I am ok with v5.8x since I am using old card GTX 1070TI and few RTX 2070 but I wanted to try new version to be prepared for future needs in case I add some newer cards RTX3 or AMD RX66xx...