I bought my Samsung Galaxy j7 next in 2017 its Wi-Fi was not working after 3 months and still it is not working but once I have went to service centre they have upgraded the system and it went well for qround 3 days and after that it start showing error whenever I am connecting to some Wi-Fi or hotspot it is showing that authentication error occurred and I have actually restarted my phone I have actually factory reset my phone but still the problem is not going what should I do...
