Firebase+Rust - bad gateway

I cannot reach my firebase db from my rust api deployed thru a docker container. The API is ok ( so I assume network is fine. I opened all rules from my firebase db (read:true/ write:true) but I still receive a http error when retrieving data from the db (e.g.
Code: GitHub - sergiorgiraldo/voting2
Anyone faced similar problem? Maybe an specific configuration for Firebase?