Baby steps at first, give it time.
Sony Computer Entertainment are finally taking meaningful steps forwards in tackling the issues that have been affecting users of the PSN since Holidays of this year. Speaking to users by way of the AskPlayStation Twitter page, they’ve said that there have been updates made to the PSN and that players can now log in without needing to change their settings.
They said, “Update for PS4 users: We’ve made recent updates to the network that should allow you to sign in without changing MTU settings.”
DulaShockers have reported that they have personally tested their connection with a default MTU setting of 1500. With that being said, they’re all too aware that there are many players who simply cannot connect due to login issues and as such, they are appealing for information from those users. You can direct your feedback to this thread that will ask you for your location, ISP, Console affected and receive errors (screenshots can be used).
Best of luck to those of you still struggling.