iphone says incorrect password for wifi

Q: "Let me try this another way... when I try to connect wireless, iPhone asks for the password. iPhone says it's the wrong password. I double/triple checked the password and it's right. HELP!" - teetime112 from Apple Community

Wi-Fi connection is so important in our everyday life that once we fail to connect it, it feels like we have disconnected from the whole world. That is true. We depend on network severely. However, many iPhone users may confront with the situation where iPhone says Wi-Fi password is incorrect even though it is correct. This circumstance could cause big troubles. Therefore, this article aims to introduce 8 effective methods for you to solve this problem.