Looks like a pilot error. Yahoo download format is below:
Date,Open,High,Low,Close,Adj Close,Volume
2018-01-02,78.269997,84.099998,76.210999,84.089996,83.483208,1217600
2018-01-03,84.000000,88.808998,83.599998,87.209999,86.580688,1342600
2018-01-04,88.660004,88.660004,82.739998,84.540001,83.929962,1113000
2018-01-05,85.230003,85.348000,81.860001,83.570000,82.966957,921900
2018-01-08,83.830002,83.830002,76.129997,78.400002,77.834267,1870900
2018-01-09,79.349998,85.150002,79.349998,84.379997,83.771111,1485800
2018-01-10,83.099998,88.080002,80.190002,87.800003,87.166451,1255700
2018-01-11,87.650002,89.900002,85.910004,89.300003,88.655624,1051900
2018-01-12,89.589996,91.599998,88.599998,90.709999,90.055428,854400
2018-01-16,91.970001,92.900002,81.599998,82.410004,81.815346,2314200
2018-01-17,86.320000,86.489998,83.013000,85.430000,84.813545,1259600

and the string format
string Format = "+%Y-%m-%d,f3,f1,f2,f4,f5,f6";