I never saw this error, but can be a symptom of corrupted acme.json contents, or bad file permissions.
To check permissions:
runagent -m traefik1 podman exec traefik ls -Rl /etc/traefik/acme
Should be
/etc/traefik/acme:
total 0
-rw------- 1 root root 0 Jul 1 09:27 acme.json
If they are correct, and you have few LE host names (so the request limit is far from being hit) let’s try to erase acme.json:
runagent -m traefik1 podman exec traefik sh -c 'umask 077; echo {} >/etc/traefik/acme/acme.json'
runagent -m traefik1 systemctl --user restart traefik