TLS or certificate errorAnswered

Having an issue getting older Apple computers activated online.

I've done this on the affected computer:

cd ~

curl -kO https://letsencrypt.org/certs/isrgrootx1.pem

curl -kO https://letsencrypt.org/certs/isrg-root-x2.pem

sudo security add-trusted-cert -d -r trustRoot -k "/Library/Keychains/System.keychain" "isrgrootx1.pem"

sudo security add-trusted-cert -d -r trustRoot -k "/Library/Keychains/System.keychain" "isrg-root-x2.pem"

I've also done this as suggested by Apple:

Download https://letsencrypt.org/certs/isrgrootx1.pem
Download https://letsencrypt.org/certs/isrg-root-x2.pem

1 Open Keychain Access.
2 Select the System keychain.

3 Double click or drag and drop ‘isrgrootx1.pem’ to install it to the System keychain.
4 Authenticate.
5 Double click ‘isrgrootx1.pem’ in the System keychain to open it.
6 Click the disclosure triangle next to ‘Trust’ to view the trust settings.
7 In the drop down menu for ‘When using this certificate’, select Always Trust.
8 Authenticate again if prompted.

9 Double click or drag and drop ‘isrg-root-x2.pem’ to install it to the System keychain.
10 Authenticate.
11 Double click ‘isrg-root-x2.pem’ in the System keychain to open it.
12 Click the disclosure triangle next to ‘Trust’ to view the trust settings.
13 In the drop down menu for ‘When using this certificate’, select Always Trust.
14 Authenticate again if prompted.

Nothing makes any difference.  We are using the latest version of Turbo Activate.