By default, Stormkit uses LetsEncrypt to issue certificates automatically. If you want to change this behaviour for specific domains, you can configure custom certificates.
To do so:
Expand (...) button and click on that.Certificate and Private key that is used while creating the certificate.Note Stormkit accepts only PEM encoded files.
If you have a certificate with a .crt extension, you can use openssl to convert it into PEM format:
openssl x509 -in example_org.crt -out example_org.pem -outform PEM