All of my passwords has just been reset

yes, as the subject goes, all of my passwords on my iPhone 7 plus has been reset, several of my chat accounts, I have to reset all the data. It keeps asking me to change all my codes every now and then.

I already reset the device passcode, after it has asked me so many times.

Just wondering what can I do so I can prevent a reset of all my accounts? And why did this suddenly happened?