Chrome Version: 69.0.3497.57
OS: Google Rodete
Cast for EDU: 18.507.0.9 (Canary)

What steps will reproduce the problem?
(1) Create a Cast for EDU receiver, e.g. mfoltz-test
(2) Visit https://googlechromelabs.github.io/presentation-api-samples/photowall/
(3) Start a presentation to mfoltz-test

What is the expected result?
The presentation starts as expected

What happens instead?
A dialog appears with "Unexpected Error - Cast for EDU needs to close"



Please use labels and text to provide additional information.

If this is a regression (i.e., worked before), please consider using the
bisect tool (https://www.chromium.org/developers/bisect-builds-py) to help
us identify the root cause and more rapidly triage the issue.

For graphics-related bugs, please copy/paste the contents of the about:gpu
page at the end of this report.