trust anchor for certification path not found

I’m getting “ERROR: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.” back as the response from doing network.request to an https address but only on a particular device (symbol/moto NC40N0)

It works in the simulator, it works on my phone, it works on the other devices I’ve tried it on running both newer and older versions of Android.

If I put the address I am connecting to into the browser on the device that seems quite happy with the certificate.
The root CA is in the list on the device in settings->security->trusted certificates

Does anyone have any suggestions on where to look next for possible causes?