Dear Samsung Member,
Greetings from Samsung Customer Support!
Please perform the below mentioned steps to resolve the issue:
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 Network Settings: Go to apps screen >Settings >General Management >Reset >Reset Network Setting.
For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).
Thank you for writing to Samsung.
Samsung Customer Support