Arcamax comics failed to download the images from resources.arcamax.com because they failed to include the intermediate CA certificate in their CA chain. The solution was to get the missing certificate for the signing authority
Sectigo RSA Domain Validation Secure Server CA
On Windows or a Linux desktop, use Firefox to get the certificate chain. Open https://www.arcamax.com/ in Firefox. Click the lock icon in the address bar. Click "Connection secure" in the dropdown and select "More information" then select "View certificate." In the "Miscellaneous" section click on the "PEM (chain)" link to download the certificate chain. Open the downloaded file with a text editor. The required intermediate certificate will be the second one.
Copy the 2nd certificate from -----BEGIN CERTIFICATE----- through
-----END CERTIFICATE----- and paste into a file named
Sectigo_RSA_Domain_Validation_Secure_Server_CA.crt
Upload this file to the Ubuntu Linux server. On the server, run the command
$ openssl x509 -noout -in Sectigo_RSA_Domain_Validation_Secure_Server_CA.crt -subject
to confirm that it is the Sectigo signing certificate.
Copy the crt file to the local ca-certificates directory using the command
$ cp Sectigo_RSA_Domain_Validation_Secure_Server_CA.crt /usr/local/share/ca-certificates/.
Update the certificates using the command
$ update-ca-certificates
It should report that it added a new certificate. The arcamax.recipe should now work.
