I've moved your post to the Help category. If you fill this form out (which the Help category has be default), it will be much easier for people to help you.
Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. crt.sh | example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
My domain is:
I ran this command:
It produced this output:
My web server is (include version):
The operating system my web server runs on is (include version):
My hosting provider, if applicable, is:
I can login to a root shell on my machine (yes or no, or I don't know):
I'm using a control panel to manage my site (no, or provide the name and version of the control panel):
The version of my client is (e.g. output of
certbot --versionorcertbot-auto --versionif you're using Certbot):
I'll see what I can do to try to point you in the right direction though.
There was a change made last week, to no longer present the expired DST Root CA X3 certificate which had been included in certificate chains by default to improve compatibility with old Android versions. Nothing should be needing it anymore unless they need compatibility with those clients. You're going to need to give more details on what system and process is showing you this error. It sounds like it doesn't know about the ISRG Root X1 certificate, which would be unusual for a "normal" OS root store.
This error is saying that you did already get 5 certificates just fine, and it has rate-limited you to prevent further abuse of Let's Encrypt's resources. Whatever problem you're having, it isn't with getting the certificate, so getting even more certificates isn't going to help you.