What steps will reproduce the problem?
(1) Install NVDA on windows
(2) Go to a page that returns ERR_INVALID_RESPONSE (Example: go/pantheon/adwdwa)

What is the expected result?
Screen reader reads the error message.

What happens instead?
The error message is visually displayed (https://screenshot.googleplex.com/nhGNXK64knM). But this is not read by the screen reader.