Please be assured and to resolve "Wi-Fi" issue kindly follow the given below steps:
1. Check device in Safe Mode:-Press and hold the Power key, when Power off icon appears > Press and hold the power off icon. To exit safe mode:-Restart your device. 2. Reset the device and before resetting the device make sure to create data backup of your device via SMART switch mobile application orhttp://www.samsung.com/in/support/smartswitchpc suite. Settings>General Management>Reset.
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report)along with screenshots, short videos and error log file, so that we can assist you accordingly. Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.