certbot/acme-dns-auth.py/letsencrypt spitting logs in /var/log/syslog at high speed

[MdeLv]

Hi,

I'm using certbot and acme-dns-auth.py for getting letsencrypt wildcard certificates.

/var/log/syslog is growing at high speed until /var/ is full (and the machine is frozen) due to the following repeated error message:

Jun 1 17:54:55 test acme-dns[555]: time="2022-06-01T17:54:55+02:00" level=info msg="2022/06/01 17:54:55 [INFO][FileStorage:api-certs] Lock for 'cert_acme_auth.example.org_https://acme-staging-v02.api.letsencrypt.org/directory' is stale; removing then retrying: api-certs/locks/cert_acme_auth.example.org_httpsacme-staging-v02.api.letsencrypt.orgdirectory.lock"

What is the cause? Is --dry-run option a possible cause?

What is the reference and complete documentation for using certbot and acme-dns (acme-dns-auth.py) on linux?

Thanks
Best regards