Got an answer to why we got that notice. Apparently when we signed up for the new plan year, and chose the HDHP, the company opened the HSA account. But we weren’t covered by HDHP until Jan 1, so we’re not eligible.
Also found out that I should open a new HSA by myself, and when retirement is “official” I can roll the funds from the employer-linked account to my personal account. Apparently there are more fees with the employer account which I would have to start paying.