Why does my mobile say WiFi not in range when it clearly is?
well, maybe sometimes low quality smartphones can be like that. try to turn the wifi connection to your mobile then connect. or maybe its on the wifi that has a problem. not with your mobile.
Details. What is your wireless network configuration? What mobile are you having troubles with?
For example some mobile device have troubles connection to a network that is sending on 2,4GHz and 5GHz simultaneously. Another issue might be e.g. your router or AP being configured for 5GHz but your mobile only supports 2,4GHz.
Try changing encryption, security, wireless channel, activate/deactivate wide channel (40MHz), etc.
try to reset your mobile, apply updates if available