Invalid enrolled certificate for testrfc7030.com

[lgtti]

I'm trying to run some test with your example server http://testrfc7030.com/
Using the instructions in the welcome page the enrolled certificate is correctly verified by openssl:

openssl verify -CAfile dstcax3.pem cert.pem
cert.pem: OK

After this, i have tried with my EST Client written using C and OpenSSL using the same CSR as before.
It works but the resulting certificate is not signed by the EST TA /cacerts result.

This is the HTTP response i receive:

HTTP/1.1 200 OK
Status: 200 OK
Content-Type: application/pkcs7-mime; smime-type=certs-only
Content-Transfer-Encoding: base64
Content-Length: 581
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If you try to parse the certificate this is the output (please note the signature algorithm!)

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 17930 (0x460a)
        Signature Algorithm: ecdsa-with-SHA1
        Issuer: CN=estExampleCA
        Validity
            Not Before: May 24 15:02:59 2023 GMT
            Not After : May 23 15:02:59 2024 GMT
        Subject: CN=IntegrationTest
        Subject Public Key Info:
            Public Key Algorithm: id-ecPublicKey
                Public-Key: (256 bit)
                pub:
                    04:a8:91:66:33:ca:d1:bc:cc:f9:c4:18:f5:e8:fc:
                    99:a7:89:cf:7d:6e:27:38:b4:33:d6:96:61:5f:87:
                    93:b1:95:63:64:20:5c:21:e4:87:2b:c2:0a:fa:27:
                    40:06:53:46:18:d1:91:c5:01:7a:f8:cb:4a:86:fd:
                    15:9f:44:3c:69
                ASN1 OID: prime256v1
                NIST CURVE: P-256
        X509v3 extensions:
            X509v3 Basic Constraints: 
                CA:FALSE
            X509v3 Key Usage: 
                Digital Signature
            X509v3 Subject Key Identifier: 
                8F:C6:E3:73:2F:EC:6E:B5:F1:9B:45:2C:7A:1B:6C:CF:2B:33:3B:82
            X509v3 Authority Key Identifier: 
                D7:D2:EC:EB:8C:D2:80:71:9C:CB:F4:46:D3:52:D1:26:AB:63:5E:2A
    Signature Algorithm: ecdsa-with-SHA1
    Signature Value:
        30:46:02:21:00:86:87:d8:ec:4c:b7:8f:dd:6a:de:5c:a9:ee:
        70:2c:86:9b:90:66:be:e8:29:05:ab:9b:10:3d:3f:a0:f5:ca:
        fd:02:21:00:fa:12:15:d9:94:3c:1c:6c:39:23:23:51:a6:75:
        9c:5a:da:d5:73:b1:bf:c2:ab:6f:c0:ed:be:ce:34:b2:45:87

Obviusly the verify command fails:
openssl verify -CAfile dstcax3.pem cert-client.pem
CN = IntegrationTest
error 20 at 0 depth lookup:unable to get local issuer certificate
cert-client.pem: verification failed: 20 (unable to get local issuer certificate)

Why i receive a certificate with a dignature SHA1? Is this signed by another CA?

NB: this is done using a P12 as client certificate connecting to port 9443. If i try to run the same test using basic auth connecting to the port 8443 the enrolled certificate is correct (validated and with SHA256 as signature algorithm).