Dear Samsung Member,
Greetings from Samsung Customer Support!
To resolve "Wi-Fi" issue kindly follow the given below steps:
1. Forget the Network:-Go to apps screen >Settings >Connections > Wi-Fi >Wi-Fi network >Tap and hold the Wi-Fi network that you're having trouble with until the menu allows you to select Forget Network.
2. Reset the device: -Kindly create data backup of your device via SMART switch mobile application or http://www.samsung.com/in/support/smartswitch pc suite.
>> Tap on Settings> Tap on General Management> Tap on Reset.
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report/ask question).
Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.
Thank you for writing to Samsung.
Samsung Customer Support