The new version of MAMP Pro automatically creates OpenSSL certificates when you check "Use SSL" for a host. This is awful and should not be something MAMP does by default. In addition, you can't create a new host first without first setting up the SSL environment....why do we need to configure this for even non-ssl hosts??
The SSL environment needs to be set-up before you can create a new host!
MAMP Pro will try to do this for you. This might trigger macOS to ask for your administrator credentials. Please provide them so MAMP PRO can save its master certificate to your keychain.