The error message displayed in Figure 1 indicates, that there are either too many documents to generate (rather unlinkely) at the moment or that the DCP service is not running.
This blog article outline how to react if your DocumentsCorePack (DCP) Service stopped working. It is most likely because the username and password credentials are not working anymore. Please note: In most of the cases this happens because the password of the Office365 account has expired. We would recommend you to "Setup your password to never expire" for the account on which you run the DCP service.
When using our products, the CRM discovery service is contacted to retrieve the service URLs for accessing the CRM WebServices.
In some cases the URL returned by the discovery service is not useable to contact the CRM WebService.
Please note: GroupCalendar v5.58 or higher is required. The feature is available for all activity types.
GroupCalendar for MS Dynamics CRM 2011 provides the possibility to define a specific color for each scheduled service activity and appointment (click here to download the latest GroupCalendar version).
Receiving a service unavailable response on a website usually indicates, that the application pool of the site is not running.
To solve this issue, open your InternetInformation Management and verify all required app pools are started.