[FizzyWater]

I could be remembering wrong, but I think I got this error message one weekend, but it was fixed sometime that Monday (I tried logging in again when I got home from work).

So if it turns out your card isn't expired, fingers crossed it was just a hiccup in the system that the admins could correct when they're back in the office.

For what it's worth, I have 3 library cards that I use to access up to 5 different Overdrive library sites. One expires annually, one every two years, and one never has. Not to say they might not change their mind on that last one at some point, but so far, I've never been asked to renew it (and it's the one I've had for a couple of decades at least).