Indeed, at 07.00hrs I couldn't get on the site, it was full! I was in some kind of virtual waiting room!
Then at 08.00 I got on but it said there were no sailings back on 8th June 2025!
When I changed to the day before  & then back to the 8th june it came up with a full day of sailings!!!
So, we're booked on the same boats again next year.

I must say I've never had a problem before, but I've always used my desktop with 5 or so browsers open, refreshing each one continuously!

EDIT- just tried again now, 08.32hrs, got straight on to the bookings, all outgoing sailings available, nearly all return boats available! (2 out of 3) very strange!