Debian 11 base: can't build because ISO is not found

When testing my CI integration, I have an issue with Debian 11 base:

==> base.qemu.debian: Retrieving ISO
==> base.qemu.debian: Trying https://cdimage.debian.org/cdimage/release/11.1.0/amd64/iso-cd/debian-11.1.0-amd64-netinst.iso
==> base.qemu.debian: Trying https://cdimage.debian.org/cdimage/release/11.1.0/amd64/iso-cd/debian-11.1.0-amd64-netinst.iso?checksum=sha256%3A8488abc1361590ee7a3c9b00ec059b29dfb1da40f8ba4adf293c7a30fa943eb2
==> base.qemu.debian: Download failed bad response code: 404
==> base.qemu.debian: error downloading ISO: [bad response code: 404]
Build 'base.qemu.debian' errored after 422 milliseconds 677 microseconds: error downloading ISO: [bad response code: 404]