Here's the remedy for the next guy who runs into this issue, just run
http_proxy="" apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 15331454B72FD7EC
inside the pbuilder chroot.
Here's the remedy for the next guy who runs into this issue, just run
http_proxy="" apt-key adv --keyserver keyserver. ubuntu. com --recv-keys 15331454B72FD7EC
inside the pbuilder chroot.