Q: cannot connect to wifi

out of no where i cannot connect my few month old iphone 6 to wifi. keep getting an incorrect password error. my password is correct. i have reset all settings many time & restored to new phone several times. I connected the phone to the router as a last try & was able to connect to wifi network when connected by a usb. i unplugged & wifi stayed connected when i was near the router. Signal was weak so I tried to restore to new phone 1 more time hoping the issue would resolve itself. Now i am back to not connecting to wifi at all. Ive literally tried everything many times. online tech support can see no issues causing this from the diagnostic test they ran. Also now bluetooth will not turn on...