Door open error but Cherry S/W is not the issue

Remove the cover to the controller and find the battery on the left side. There may be a strip of plastic keeping the battery from making contact, remove plastic strip. If this doesn't resolve the issue, remove the board the battery is connected too and re-seat all the connection on it.​

If that doesn't work, go in to the AGS folder at C/AGS/AGStablesStax/Assets and find the Config.xml file.  Open it, if it doesn't contain any code, you need to replace that file from a known good controller.