This error can occur when there is a Server Principal Name (SPN) issue for the CRMFrontEndServer server. You can receive this error for any plugin published in the sandbox. It will only happen if the sandbox service is not installed on the same server as CRM web site and kerberos authentication is enabled for the website.
Steps to resolve:
- Check Windows Event Viewer on CRM server for Kerberos client error.
- The error will indicate the service account and the needed SPN.
- Use the following command to list all the SPNs registered for the serviceaccountname.
setspn –l domain\serviceaccountname
The command displays only the SPN registered on the HTTP/CRMfrontEndServer.CRM.domainname.com (Fully Qualified domain name of the CRM front end server).
- Add a new SPN on the servername using the following command:
setspn –a http/CRMFrontEndServer domain\serviceaccountname .
- Restart the sandbox service