How to add 2 Withings Users

Hello,

I just installed 2 ‘Withings Sleep Analysers’ for my partner and I. I’ve already added one User to Homey via the Withings App and it works great, but I’m not able to add a second user at all. Am I doing something wrong, or is it not possible to add 2 Withings Users in Homey?

Withings Sleep Analyser