Quote Originally Posted by Dzian View Post
The tick box doesn't save your password... it's been a gripe for many players for as long as I can remember...
It does on PS4 since 5.0 ^^

However, I heared of OP's problem before, and it came out that that person was filling in an one time password without having an one time password registered.

Other problems are when you log in from different devices, wich changes your IP and SE forces you to change your password because of security (doesn't happen when you have an one time password registered).