Where country has area code 771?

According to Verizon's website. there is no 771 area code in North America (USA, Canada, etc.).

Mexican area code 771 is the area around Pachuca de Soto, Hidalgo. Landlines are +52 771; mobiles are +52 1 771.

An international number beginning +7 71 is a landline in Kazakhstan.

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, and many other countries use different prefixes.)