low share difficulty

[helloword2013]

I have set up a lyra2z nomp pool for zcoin,but when submit share of cpuminer it is low share diff reject
CPUminer:

Code:

[2017-02-14 14:14:19] factor reduced to : 0.00
[2017-02-14 14:14:19] CPU #0: 39083.76 H/s
[2017-02-14 14:14:19] accepted: 0/31 (0.00%), 39083.76 H/s booooo
[2017-02-14 14:14:19] reject reason: low difficulty share of 8.503107751490837e-8

pool:

Code:

2017-02-14 14:14:22 [Pool]  [zcoin] (Thread 1) Share rejected: 

{"job":"1","ip":"43.241.232.45","worker":"a74DojFWKFH9a1KdCKBfY6e9t2H8irUx8i","difficulty":0.001,"error":"low difficulty share of 8.503107751490837e-8"}

who can help me to fix it

[Prelude]

Gpu is unstable.  Increase voltage or lower clock speeds.