The error message says
"An error has occurred
A server with the specified hostname could not be found"
Dump of the log when I try to do an update is below
May 2 20:29:05 USHB-347de6 Software Update[1338]: SUAppStoreUpdateController: found in cache: <none>
May 2 20:29:14 USHB-347de6 installd[1349]: installd: Starting
May 2 20:29:14 USHB-347de6 installd[1349]: installd: uid=0, euid=0
May 2 20:29:14 USHB-347de6 Software Update[1338]: SUAppStoreUpdateController: making scan unconditional since did not register local on last scan
May 2 20:29:14 USHB-347de6 Software Update[1338]: SoftwareUpdate: Scan for client pid 1338 (/Applications/App Store.app/Contents/MacOS/App Store)
May 2 20:29:14 USHB-347de6 Software Update[1338]: SoftwareUpdate: Error encountered in scan: Error Domain=NSURLErrorDomain Code=-1003 "A server with the specified hostname could not be found." UserInfo=0x7fd7f225f570 {NSUnderlyingError=0x7fd7f6902b30 "A server with the specified hostname could not be found.", NSErrorFailingURLStringKey=http://usrv-macman1.na.uis.unisys.com:8088/index.sucatalog, NSErrorFailingURLKey=http://usrv-macman1.na.uis.unisys.com:8088/index.sucatalog, SUCatalogFetchOverrideURLString=http://usrv-macman1.na.uis.unisys.com:8088/index.sucatalog, NSLocalizedDescription=A server with the specified hostname could not be found.}
May 2 20:29:15 USHB-347de6 Software Update[1338]: SUAppStoreUpdateController: scan (f=0, c=0, p=1, r=1) got error A server with the specified hostname could not be found.
May 2 20:29:15 USHB-347de6 Software Update[1338]: SUAppStoreUpdateController: making scan unconditional since did not register local on last scan
May 2 20:29:15 USHB-347de6 Software Update[1338]: SoftwareUpdate: Scan for client pid 1338 (/Applications/App Store.app/Contents/MacOS/App Store)
May 2 20:29:15 USHB-347de6 Software Update[1338]: SoftwareUpdate: Error encountered in scan: Error Domain=NSURLErrorDomain Code=-1003 "A server with the specified hostname could not be found." UserInfo=0x7fd7f20c9830 {NSUnderlyingError=0x7fd7f23d8190 "A server with the specified hostname could not be found.", NSErrorFailingURLStringKey=http://usrv-macman1.na.uis.unisys.com:8088/index.sucatalog, NSErrorFailingURLKey=http://usrv-macman1.na.uis.unisys.com:8088/index.sucatalog, SUCatalogFetchOverrideURLString=http://usrv-macman1.na.uis.unisys.com:8088/index.sucatalog, NSLocalizedDescription=A server with the specified hostname could not be found.}
May 2 20:29:16 USHB-347de6 Software Update[1338]: SUAppStoreUpdateController: scan (f=0, c=0, p=1, r=1) got error A server with the specified hostname could not be found.
Thanks