Error: Certificate uses unsupported signature algorithm

[Hr46ph]

I have a script that automatically renews my vcenter certificates. Must have been after some update but I noticed my certificates are no longer being accepted my vcenter. They renew just fine its just that I receive this error message:

Exception caught for provided certificate - /root/.acme.sh/vcenter.internal.domainname.net_ecc/vcenter.internal.domainname.net.cer. Error: Certificate uses unsupported signature algorithm - ecdsa-with-SHA384. Only SHA-2 RSA algorithms are supported on the vCenter Server.
Status : 0% Completed [Operation failed, performing automatic rollback]

I've been looking into how I can change this and from what I gather, renewals use the original key type and length that was previously used.

Somewhere I found that setting the keylength to 2048 forces signing with RSA. When I did that and used --force to renew, the certificates got rejected with the same message.

I changed the default CA back to Let's Encrypt (from ZeroSSL) and tried again, but got the same error message.

I then read somewhere that it might not use what I specify on the commandline when there are previously saved renewals with conf found, so I removed the mydomain.net/ directories (actually, I moved them ;) ) and forced again. It recreated everything, and still the certificates are being rejected with the same error message.

OpenSSL shows me the following:

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            ....
        Signature Algorithm: sha256WithRSAEncryption
        Issuer: C = US, O = Let's Encrypt, CN = R3
        Validity
            Not Before: Dec 27 14:21:45 2023 GMT
            Not After : Mar 26 14:21:44 2024 GMT
        Subject: CN = vcenter.internal.domainname.net
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)

I don't know but that looks like SHA-2 RSA to me, with 2048 keylength? But then further down I see this (no idea if it has any impact):

X509v3 extensions:
            X509v3 Key Usage: critical
                Digital Signature, Key Encipherment
            X509v3 Extended Key Usage: 
                TLS Web Server Authentication, TLS Web Client Authentication
            X509v3 Basic Constraints: critical

So its all X509v3. When I check this page:
https://core.vmware.com/vmware-vsphere-8-default-ssltls-cipher-suites#section1

It doesn't list x509v3 in the first collumn. But I am going out on a limb, maybe its something else entirely I don't know.

If someone can help me out here I would greatly appreciate it!