One of the unique features with Kobo ereaders is the fact that they have OverDrive support built-in for borrowing ebooks from public libraries. But a recent change has taken away the ability to use multiple libraries on Kobo devices directly.
Kobo has always been pretty vague about supporting more than one library on Kobo ereaders, but you used to be able to sign-in using an OverDrive account in order to access multiple libraries at one time on Kobo’s devices.
Now the option to sign-in using an OverDrive account has been removed.
Kobo seems to be blaming OverDrive and OverDrive appears to be blaming Kobo, with no real solution being offered by either party.
I think it goes back to the fact that OverDrive, for some misguided reason, decided to phase out their OverDrive branding in favor of Libby. They spent years building up the OverDrive brand and the OverDrive app, and then they decided it would be better to push a new Libby app with Libby branding instead that does pretty much the exact same thing.
So for the past several years most things OverDrive related have been transitioned to Libby, and the OverDrive login option on Kobo ereaders is just another one of the dominos to fall.
I think it still might be possible to borrow from multiple libraries on Kobos if you were already signed-in with your OverDrive account (could someone confirm this in the comments?), but that option no longer exists so you might want to avoid resetting or logging out of OverDrive on your Kobo ereader.
There are a few workarounds to still be able to use multiple libraries on Kobo’s devices, but they aren’t as convenient as the old method.
Workaround #1
The sign-in, sign-out option. It’s a bit tedious, but you can sign-in using one library card, then sign-out when your done reading your borrowed library ebook. Then sign back in with a different card and repeat.
Workaround #2
The old school method. You can use Adobe Digital Editions to download ebooks from multiple libraries and use it to sideload the ebooks onto your Kobo device using a computer. This is how it generally works with other devices that don’t have OverDrive support built-in.
See here for directions on how to use ADE with Kobo ereaders to sideload library ebooks.
Workaround #3
Multiple Kobos for multiple libraries. Granted, this isn’t the best option for everybody, but some people have more than one Kobo ereader. You could use different libraries for different Kobos. I’m curious how this would work because I just use one library, and ebooks that I borrow on one Kobo device show up (and work) on other Kobos, even ones that aren’t logged into my library at all.
For whatever reason, I’ve only ever seen one of my libraries when signed in with Overdrive. I just sideload the ones from my other one.