Comment by xorcist
I don't know what your issues are, but perhaps the know-it-all people who comments on this with a variation of "you're doing it wrong" or a problem of "not enough automation" could cool down a bit and realize the web PKI is hacks build from hacks and there are many reasons why the public ACME system may not be entirely robust for every application.
On the top of my head, that could be because one or more domains are not accessible from the public Internet (which could be for a variety of reasons), a subset of the subject domains having expired for legitimate reasons but you might not know which in advance (certificates being what they are some application rely on them having alternative names), intermittently flaky routing (which might not be a problem for the application), and a number of other reasons. That's without including potentially hostile actors. Then there are plenty of offline uses for certificates!
That said, Let's Encrypt has really been a revolution and made life better for many people. But it's not perfect and the PKI system itself has many warts. It's absolutely a system that may need a non negligible amount of babysitting when you venture outside the absolute mainstream.
If you're using LetsEncrypt without automation you're doing it wrong, and the reason that the WebPKI is so hacky is that it was insulated from basic computer science for 2 decades and run by enterprise software companies.
You have to automate certificates. You can't do these by hand anymore. Certificate lifetimes are going to get inexorably shorter.