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.
You do not appear to have requested a certificate in three months.
Your renewal schedule seems to be longer than standard. The default is to renew after sixty days which leaves thirty days to troubleshoot. How are you obtaining and renewing your certificates?
Let's Encrypt would not issue expired certificates. It may seem like that to you, but unless somehow, while issuing more than 5 million (!!!) certs daily (that's about 58 certs PER SECOND!) Let's Encrypt suddenly broke, it's way more likely something didn't go correctly on the client side with your ACME client.
Unfortunately you did not bother to answer 8 out of the 9 questions of the questionnaire. So unless you actually provide the information asked, we can't help you.