I am using certmonger on Ubuntu Server 22.04 (Jammy Jellyfish) to request a certificate from FortiAuthenticator (FAC v8.0) via SCEP. The enrollment request successfully reaches FAC and I can see and approve it in the FAC GUI. However, certmonger fails after approval with the following error:

status: CA_UNREACHABLE
ca-error: Error: failed to verify signature on server response.
error:0688010A:asn1 encoding routines::nested asn1 error

Full journalctl output:

certmonger[3989]: -----END PKCS7-----
scep-submit[3989]: error:0680009B:asn1 encoding routines::too long
scep-submit[3989]: error:06800066:asn1 encoding routines::bad object header
scep-submit[3989]: error:0688010A:asn1 encoding routines::nested asn1 error
certmonger[2452]: Error: failed to verify signature on server response.
error:0688010A:asn1 encoding routines::nested asn1 error