When attempting an electronic signature with DAQSTANDARD Viewer, error E0210, "Not registered user." appears. My user name, ID, and password are correct, and I confirmed my signature privileges on the main unit.

It is possible that the user has expired and the password has returned to the default, or some similar problem. See section 2.10, "Signing Batch and Continuous Data" in DXA120 DAQSTANDARD Viewer User's Manual.