After a network configuration reset on my iPhone all Wi-Fi passwords were lost. They were stored in iCloud Keychain, synced with my Mac, where they disappeared too. This is very frustrating since it seems that they were store only on iCloud and I can't restore them via old Time Machine backups.
(In Keychain on my Mac I have only some of them, 90% are lost.)
IPhone – Lost Wi-Fi passwords after reset network settings on iPhone
icloudiphonekeychainpasswordwifi
Best Answer
I came across this question and this was suggested by someone on a forum:
Note that I haven't tested this personally, but I just came across this because I'm trying to debug a problem when my iPad disconnects from WiFi only when streaming Netflix.