@Ajeet83 

Hi, do you mean your mobile phone is unable to connect the WiFi network of TL-WR845N? What is the error message?

Please make sure the wireless password is entered correctly and check if the same password work on other wireless client devices.

If the issue happens with the mobile phone only, please also try to change wireless channel on Advanced->Wireless->Wireless Settings page, or even change the wireless network name and password for a try.