HLS and SSL issues

I’m having trouble streaming using HLS encoded with SSL. Our HLS SSL streams seem to work everywhere except on Roku.

Here’s the relevant code:

  port = CreateObject("roMessagePort")
  screen = CreateObject("roVideoScreen")

  screen.SetMessagePort(port)
  screen.SetPositionNotificationPeriod(1)
  screen.SetCertificatesFile("common:/certs/ca-bundle.crt")
  screen.SetCertificatesDepth(8)
  screen.InitClientCertificates()

I end up getting:
Roku internal error: 1
Error message: The format is not supported or the media is corrupt.

We are using a pretty standard certificate (RapidSSL/GeoTrust). Is that not included in ca-bundle.crt? I tried using a few of the root pem files from GeoTrust, but that didn’t seem to change anything.