Hi and welcome to the Forum
Since it's an upgrade, you need to ensure your proxy should should accept the SUSE domain (or at least selected
sites like updates.suse.com) without authentication.

You need to populate proxy setting in YAST and to add two lines with your proxy information to /etc/profile, for example:

export http_proxy="http://10.10.1.1:8081/"
export https_proxy="https://10.10.1.1:8081/"

The above needs to be in /root/.curlrc as well.