the functions for WIF and private key are wrong or out-of-date,
they generate a WIF of length 51, but actually we use WIF of length 52.
for example:
5K7T2qR7K5MUMDmkJvCEPbUeALuPyc6LFEnBiwWLuKCEVdBp8qV length 51
L1aW4aubDFB7yfras2S1mN3bqg9nwySY8nkoLmJebSLD5BWv3ENZ length 52
the functions for WIF and private key are wrong or out-of-date,
they generate a WIF of length 51, but actually we use WIF of length 52.
for example:
5K7T2qR7K5MUMDmkJvCEPbUeALuPyc6LFEnBiwWLuKCEVdBp8qV length 51
L1aW4aubDFB7yfras2S1mN3bqg9nwySY8nkoLmJebSLD5BWv3ENZ length 52