Traefik will also generate SSL certificates using letsencrypt. LetsEncrypt has some rate limits to ensure fair usage. If you hit the error too many certificates already issued for exact set of domains then your traefik container probably restarted more than 5 times because every restart leads to a certificate renewal.
Table of contents
4 Ways to fix LetsEncrypt SSL Generation with Traefik in KubernetesIssue 1: No Host() rulesIssue 2: LetsEncrypt production serverIssue 3: LetsEncrypt Rate LimitsIssue 4: CAA record3 Impressions