BIT-Z.com has changed their API service after their last maintenance,..
all API URLs/JSON field names have been changed.

https://apiv2.bitz.com/Market/ticker?symbol=btc_usdt

https://apiv2.bitz.com/Market/ticker?symbol=esn_btc

Please see:
https://apidoc.bit-z.pro/en/market-quotation-data/Get-ticker-data.html