This document provides a gentle introduction to the data structures and formats that define the certificates used in HTTPS. It should be accessible to anyone with a little bit of computer science experience and a bit of familiarity with certificates. An HTTPS certificate is a type of file, like any other file. Its contents follow a format defined by RFC 5280. The definitions are expressed in ASN.1, which is a language used to define file formats or (equivalently) data structures.| letsencrypt.org
When entering the fullchain.pem certs, I'm getting BER: residual data after 'constructed' data That's in the GUI of the Communigate Mail Server. This used to work flawlessly in the past, but this seems to be an error preventing me from fullfilling the cert update. Any ideas?| Let's Encrypt Community Support