WiFi says incorrect password
In our house we have 2 pieces of iPhone 6 and an iPad Mini, all purchased about 5 years back. They are now running iOS 12.4.8. Everything was working fine till last month when suddenly 1 iPhone started saying "Incorrect Password" for my wifi. Tried everything suggested but no luck. This iPhone and the iPad is signed in with same apple ID while the remaining iPhone has different id. What happens is this:
- iPhone says incorrect password for wifi. I have 5 more devices at home which connect to wifi with same password.
- this iPhone connects to any other wifi outside my home.
- At home if I switch off my modem+wifi, then turn on personal hotspot on the second iphone, then this problematic iphone connects to hotspot. Then if I switch back my modem and wifi, it happily connects to wifi. (my wifi and hostspot have different passwords and of course different SSIDs)
- When my modem and wifi is ON, it says "Incorrect Password" even for my hostpot.
- Once it connects to my wifi, it remains connected without any issue. If I power cycle my wifi it automatically connects to it
- However, if I power cycle the phone, it again says "Incorrect Password"
Tried all things such as:
- Forget network
- Rest network
- Factory reset phone
- Factory reset through iTunes
- Changed wifi SSID and Password
- Did a full reset of wifi router (D-link DIR-600M)
- Tried using a different wifi router
- Ensured all settings of wifi as per Apple recommendations (Recommended settings for Wi-Fi routers and access points - Apple Support)
Nothing seems to solve th problem, its just driving me nuts. I took the problematic phone to apple store, it connected to their wifi and the store guys simply say "buy new phone, we wont repair it". I took it to my office, there also it connected to wifi without issue.
Please help.
iPhone 6, iOS 12