I'm a (non-local) member of both Singapore and Philadelphia and I'm having no trouble getting in; I just accessed both less than 20 minutes ago and they worked fine
I've had this same problem with all my Overdrive libraries at some point; usually, I just have to wait it out and it fixes itself after some hours, or a day or two. A friend told me she had the same problem recently with one of her libraries and it was fixed when she cleared her cache so maybe that's worth a try.