it's a call from an individual or a private operating company in Hangzhou, Zhejiang province. it may be a fixed-line telephone to promote advertisements, a fraudulent telephone, or a company telephone rookie post.

If your mobile phone number or fixed telephone is opened in Hangzhou, Zhejiang, the caller ID may not display the front area code 571, but only the back local telephone number. When you query the local fixed telephone number, if you don't enter the area code, the system will automatically prompt you for the local telephone area code.