Hi szymon_dybczak,

I have also tried it in my personal Azure subscription, so that I'm sure that all traffic is allowed, but I still can't get it to work

TOKEN = "eyJ0eXAiOiJKV1QiLCJub25jZSI6InVnSVJ0a1pyLWdi................."
ORGANIZATION = "mhofman37"
PROJECT = "6121f0ba-31c2-407b-80e0-ccd1a57ce8e4"

%pip install adal --index-url "https://{TOKEN}@{ORGANIZATION}.pkgs.visualstudio.com/{PROJECT}/_packaging/test/pypi/simple/"

The service principal has permissions on the feed

Kind Regards,
Marco