How do I get the Certificate Authority Bundle?


Hi, newbie here.

I’ve successfully installed and run letsencrypt on my Mac, and used it to generate a certificate for a test subdomain on my site,

I ran ./letsencrypt-auto certonly --manual and followed the prompts, including logging in to my site via ssh so that I could provision the file needed for the “.well-known/acme-challenge” part. Eventually, the result was four files:

  • privkey.pem
  • fullchain.pem
  • chain.pem
  • cert.pem

I then logged into the control panel on my site, and uploaded the “fullchain.pem” and “privkey.pem” files as directed. I left the CABUNDLE upload empty, since I did not know which file to use for that. Then I attempted to activate ssl for the subdomain, and received the following error message:

The certificate could not be installed on the domain “”.
error Certificate verification failed!
The system did not find the Certificate Authority Bundle that matches this certificate.
Contact “Let’s Encrypt” to obtain the Certificate Authority Bundle for “Let’s Encrypt Authority X1”.

So my question is: is this an expected error, have I missed something, or do I really need to get the CABUNDLE file from Let’s Encrypt? If so, how do I get it?

Many thanks in advance.


Try uploading cert.pem for where you used fullchain.pem and chain.pem for “CABUNDLE”.


Yes! That was the solution, thank you very much!

Since this was essentially a documentation problem (or maybe an inability on my part to find the right documentation), may I suggest an improvement to the docs? I could make a pull request on github if I’m permitted to contribute.


Sure, anybody is permitted to, it’s an open source project :wink: