Can't save to library from Stock website

Having a problem where I can't save to a CC Library from the website. I'm able to search, license and add to a Library directly from InDesign, but when searching via the website, I'm getting the error above (I blacked out the Library name). I've tried both Chrome and Safari, no luck.
Wondering if this may be because I recently switched accounts? I tried deleting CoreSync because that was stuck for a while, seems fine now. The Library I'm trying to save to was created by exporting the one on my previous account and importing into the new one. I'm not sure how the mechanics between saving to a Library from the website work, I assumed it was behind the scenes web magic, but wondering if there's some preference confusion happening on my system with my old account, PS/AI/Indd all seem to working fine. Any other suggestions?
