Since January 15th 2014 Zendesk API V1 has switched to a newer version.
If you used the Zendesk integration before the mentioned date above, you’ll have to complete your login data again for the Zendesk application. Zendesk has changed part of its system, so we had to make a little readjustment in order for the integration to remain functional. You’ll need to provide a token from Zendesk, instead of your Zendesk password, as before. Here is a tutorial on how you can reactivate your Zendesk integration.
If this wasn’t the problem and you’re still receiving warning messages, contact us.