LINUX | Let’s Encrypt: too many certificates already issued for exact set of domains

Let’s Encrypt has a fair usage policy and a rate limit is set. The current limits are
a) 5 duplicate renewal certificates per registered domain per week.
b) 50 certificates per registered domain per week

You can use Let’s Encrypt’s staging environment if you are testing/dry running automation.

Further reading:
https://letsencrypt.org/docs/rate-limits/
https://letsencrypt.org/docs/staging-environment/