error in rpi 3b

[blasteffect]

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Failed to get extranonce2_size
for this command
./cpuminer -n 1048576 -o stratum+tcp://eu.luckpool.net:3960 -u wallet.pi -p password -t 0 -1 4 --cpu-affinity-stride 1 --cpu-affinity-default-index 0 --cpu-affinity-oneway-index 4