The App Center configurator requires the SSL certificate files be uploaded individually and not be protected with a password-based symmetric key (standard-PKCS12).
"Invalid file type, pfx is not allowed"
The following two certificates need to be extracted from the PFX certificate file and uploaded to the App Center server:
Note: This command also may be ran on the workstation accessing the App Center configurator console and does not have to be done on the App Center server itself. This would require openssl be installed on the accessing workstation.
App Center on-premise
Cent OS/RHEL 5.8