/etc/cron.daily/logrotate File exists error

I'm receiving email alerts showing:

/etc/cron.daily/logrotate:
error: error creating output file /var/log/nginx/openmediavault-webgui_access.log.1.gz: File exists
error: error creating output file /var/log/nginx/openmediavault-webgui_error.log.1.gz: File exists
run-parts: /etc/cron.daily/logrotate exited with return code 1

shouldn't logrotate be able to handle deleting previously rotated logs?

even after manually deleting, it keeps happening

Almost never (reboot). No (plugin)

Still happening

This looks like an answer. I deleted /var/log/nginx/*.gz - we'll see if it was just as simple as that