There has been posts lately, randomly happening. One of many posts (here) and (here)
There have been issues in the past with Netflix either the info disappearing or even would save wrong username or password, yet they were being input right.
I know a time before many just had to wait as the more you try to log in the worst it will get. And until enough people report the issue, there won't be a fix to streamfab.
I make it a point now, once logged in, to save the cookies from SF and many times restoring them, if I get logged out and can't log in, can sometimes work.
Continuing uninstalling and installing again and clearing files most likely will not help this specific issue.
Hope it clears up or gets fixed, I am luckily still logged in to Netflix via SF.