If you receive an error from Google while syncing that looks like the following:

The HTTP server returned an error: HTTP/1.0 401 Token invalid - Invalid token: Stateless token expired
Content-Type: text/html; charset=utf-8
Date: Fri, 06 Nov 2015 15:03:22 GMT
Expires: Fri, 06 Nov 2015 15:03:22 GMT
Cache-Control: private, max-age=0
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
Server: GSE
Accept-Ranges: none
Vary: Accept-Encoding

GENERAL ERROR

Do the following for each syncing account receiving this error:

1) Choose File > Syncing.

2) Select the Google syncing account in the list to the left.

3) Click either the Contacts or Calendar tab.

4) Click Reauthorize in the lower-right corner of the syncing window to login to your Google account and reauthorize SuccessWare syncing.