Interference with org agenda

[anthrolisp]

With the company-org-roam package enabled, I get the following error when I try to call my org-mode agenda:

org-agenda-get-deadlines: Symbol’s value as variable is void: org-priority-highest

This started this morning. Was fine yesterday. I went through my config, turning off/on packages one at a time until it worked. When company-org-roam is not called, it works. When it is, it doesn't. Here's my config:

(use-package company-org-roam
  :straight (:host github :repo "jethrokuan/company-org-roam")
  :config
  (push 'company-org-roam company-backends))

Any ideas? Many thanks in advance!