I need to call an external API from Salesforce. I have 3 different sandboxes (Dev, QA, Training) that point to the same external QA API endpoint. Is it possible to create a single CA signed certificate and use it across my 3 sandboxes? Should I create an individual certificate for each of the sandboxes? My domain for dev sandbox would be mycompany--dev.cs7.my.salesforce.com as of now when I get the certificate signed. What will happen if Salesforce switches my sandboxes from one instance to another later on (example CS7 to CS20)? Please suggest/share your experience.