Sony is fighting a "huge backlog" of PSN password requests.
User-requested password reset emails have been generated but can't be sent - and they have clogged Sony's ISP.
"There is still a huge backlog of emails with the ISP and waiting to go through," PlayStation blog manager James Gallagher explained. "All we can say is please wait and they will all go through as the massive demand eases."
Eurogamer has today recieved reports from users who are yet to receive their email - nearly two days after Sony turned PSN back online in the UK.
Sony forced a mandatory firmware update on users upon the PlayStation Network's return. Users were then required to change their password.
Been waiting more than 24 hours? You'll need to send another request. Sony has said they're automatically deleted after 24 hours.
"If you have been waiting for more than 24 hours than it may be worth submitting a new request now," Gallagher cautioned. "Each email has a 24-hour expiry. Just be sure to only submit the request once."