ACM import certificate error - The certificate chain provided is not in a valid PEM format.

Question

hi, I'm trying to import a letsencrypt ssl certificate. It is working ok with apache on a EC2 server, but I keep getting errors when importing to ACM.
The certificate file which works is actually a bundle with the certificate itself and the chain, so I proceed to extract it:
```
openssl x509 -in mycert.crt -out chain.pem -outform PEM
```
This just cuts the first part of the crt file, starting from ----BEGIN CERTIFICATE ---- to ---END CERTIFICATE ---. I paste this on the ACM form.

The key is a few lines base64 encoded enclosed in -----BEGIN EC PRIVATE KEY-----
and ---- END EC PRIVATE KEY-----. I paste this as is.

Then the chain I tried a number of things: pasted the two remaining certificates from the original crt file, extracted them from the live site, and a few more I dont remember. Also tried inverting first and second in case they are swapped. 
No matter what I try always get the no valid PEM format error.
The pasted code looks like this:
```
-----BEGIN CERTIFICATE-----
.....base64 stuff ....
-----END CERTIFICATE-----
-----BEGIN CERTIFICATE-----
.....base64 stuff....
-----END CERTIFICATE-----
```
Please advice

Answer

From

> ----BEGIN EC PRIVATE KEY-----

You are trying to import a Let's Encrypt ECDSA cert. 
If I recall correctly, one of the intermediate cert is RSA.

ACM only accept imports when TLS and *all* intermediate certs are ECDSA. 
As a workaround, you can [import cert into IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_server-certs.html)

Alternatively, [AWS Certificate Manager now supports Elliptic Curve Digital Signature Algorithm TLS certificates](https://aws.amazon.com/about-aws/whats-new/2022/11/aws-certificate-manager-elliptic-curve-digital-signature-algorithm-tls-certificates/).  You can request a Elliptic Curve Digital Signature Algorithm (ECDSA) P-256 or P-384 cert directly from ACM instead of using Let's Encrypt cert.

ACM import certificate error - The certificate chain provided is not in a valid PEM format.

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