Please try all of the following steps in order, until the error is resolved. 
  1. Verify that the Raiser's Edge Web Services server is on and running smoothly.
  2. Try to log into the Raisers Edge client directly on the RE7 WS server.
  3. If the Raiser's Edge has been removed or has not yet been installed on the RE7 WS server, installing RE should resolve this issue.
To access the testconfig page:
If NetCommunity is on version 7.0 and below, go to: [netcommunityURL]/testconfig.aspx. 
If NetCommunity is on version 7.1 and above, refer to Access is denied warning when trying to view testconfig.aspx