Originally Posted by
purple1addict
Normally 48 hours to the exact second

but I also had trouble checking in online yesterday and it was a good couple of hours later before I was able to complete check-in so keep trying.
I think once before on here someone commented that your connecting flight should be within 60 hours of your check-in for the first segment (although I haven't personally encountered that before) - could that be your issue?
Otherwise probably just some gremlins in the system!
Indeed, must have been gremlins in the system. I managed to check in about 40 hours before departure.