Shelly UNI light on, but no wifi

Hi all,

A total noob here. I bought Shelly Uni to connect to my doorbell to integrate it into HA. The doorbell runs on around 17 volts DC, but shows very low Amp reading. When I connect the Uni to it, I get the red light on the uni, but I can't find the device WiFi hotspot. I tried finding it with Shelly app with no success. I am suspecting the low amperage might be the cause. If so, then what is the minimum amperage required to operate the uni, and what options would you suggest?

Please tell me if I am doing something wrong.

Any help will be much appreciated.