Publishing / Checking Schema Issue

Hello, our team started getting the following error when publishing schema:

$ apollo schema:publish --key="MY KEY WAS HERE" --endpoint=".tmp\introspection.json"

√ Loading Apollo config
√ Fetching current schema
× Publishing phunware-dev to Apollo Engine
→ Unexpected token < in JSON at position 1
» Error: Unexpected token < in JSON at position 1

We haven't change anything, since the last successful push command, and I have no clue how to debug what is the underlying issue. The schema seams fine perfectly formatted JSon.

Edit: We are using Apollo 1.9.2

No source file or test is named. Start by reproducing the Apollo CLI 1.9.2 `schema:publish` command with the shown endpoint and inspect the response producing the JSON parse error; done means identifying the cause and confirming a successful schema publish or a documented workaround.

Written by the indexing model from the issue text.