At dataJAR, I recently worked with a customer which wanted to make use of Jamf Pro’s Enrollment Customization option.

However, with everything setup, we were presented with the message “Error <kCFErrorDomainCFNetwork:303>” whenever trying to load any of the defined PreStage Panes.

I reached out to Jamf Support, but they hadn’t see this issue & searching the macadmins Slack didn’t bring up anything either.

Long story short (& in an attempt to not create my own DenverCoder9 moment), we discovered the issue to be down to the environments ingress controller being configured with HTTP/2 support by default.

As soon as we disabled HTTP/2, everything worked as expected.

Hope this helps someone else too.