Let's Encrypt certificate expiry.
2021-09-29
On October 1st 2021 the old Let’s Encrypt root certificate will expire, and as such HTTPS connections secured by that certificate will not work anymore.
The change will impact many platforms and probably your PBX too.
This new tutorial will help you figure out what to do.
Read more: https://www.queuemetrics.com/blog/2021/09/29/lets-encrypt-tutorial/?lid=N293