Rolls have the following in their description:

CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_chromium_archive_rel_ng;master.tryserver.chromium.mac:mac_chromium_archive_rel_ng

The linux_chromium_archive_rel_ng bot has apparently been retired and the rolls fail to land.
A temporary fix is to just remove "master.tryserver.chromium.linux:linux_chromium_archive_rel_ng;" from the CQ_INCLUDE_TRYBOTS line and manually send it to the CQ.