Can't edit any content

I can log into and view my site, logs, etc. from the app just fine, but can't edit any nodes. Why I try, upon clicking submit I get "Wrong response format. Unable to parse response, the expected format is valid JSON."

Here is the output of drupad/check-config/1.4:
{"meta":{"version":"1.4","drupal_version":"7.12","version_match":true},"content":{"callbacks":["comments","content","content-forms","users","updates","status-report","offline","cron-tasks","dblog","cache"],"modules":["comment","node","field","user","update","system","dblog"],"permissions":["access comments","administer comments","post comments","post comments without approval","access content","administer nodes","create \/ edit content with Drupad","administer users","administer site configuration","access site reports"]}}