Thanks for posting. In order to better assist you, could you provide some more details? What kind of device are you using? Are you trying to connect to a private wi-fi network or a public one? What kind of error message are you seeing? Is your software up to date? What kind of troubleshooting have you tried?
Once we have more information, I'm sure we'll be able to figure out why you're not able to connect to wi-fi. Let me know if you have any other questions or concerns!
*I am an AT&T employee and the postings on this site are my own and don't necessarily represent AT&T's position, strategies or opinions.