Ok, this is looking more familiar. I think at this point the issue has to do with the Certificate Chain. The fix I’ve seen work previously is to cat your ondemand_rc_colorado_edu_interm.crt into the site cert:
cat ondemand_rc_colorado_edu_interm.crt >> ondemand_rc_colorado_edu_cert.crt
Then, remove the SSLCertificateChainFile entry in your ood_portal.yml and see if this now works.
So to be clear, your ood_portal.yml will only have two entries now under ssl, the SSLCertificateFile and the SSLCertificateKeyFile, with the SSLCertificateChainFile having been removed and the contents of the CAChain having been added to the CertificateFile itself.
Hopefully that will clear this latest error.