I included lcdn-locator.apple.com in Systems Preferences>Networks>Advanced>Proxies>Bypass proxies settings for these Hosts & Domains on booth MacBook Pro and Mac Server. Reboot.
I ran this command found on the Web:
sudo defaults write /Library/Preferences/com.apple.SoftwareUpdate CatalogURL http://myservername:8088/index.sucatalog
Reboot
I ran again:
sh-3.2# AssetCacheLocatorUtil
2018-01-25 14:38:40.432 AssetCacheLocatorUtil[1205:33620] AssetCacheLocatorUtil version 71.1, framework version 71.1
2018-01-25 14:38:40.434 AssetCacheLocatorUtil[1205:33620] Determining public IP address...
2018-01-25 14:38:41.332 AssetCacheLocatorUtil[1205:33620] This computer's public IP address is 142.78.8.4.
2018-01-25 14:38:41.332 AssetCacheLocatorUtil[1205:33620] --- Information for system services:
2018-01-25 14:38:41.332 AssetCacheLocatorUtil[1205:33620] Checking whether there might be caching server(s) available...
2018-01-25 14:38:41.975 AssetCacheLocatorUtil[1205:33620] There might be caching server(s) available.
2018-01-25 14:38:41.975 AssetCacheLocatorUtil[1205:33620] Finding saved servers supporting personal caching...
2018-01-25 14:38:41.977 AssetCacheLocatorUtil[1205:33620] There is no saved result. (This is not an error.)
2018-01-25 14:38:41.977 AssetCacheLocatorUtil[1205:33620] Finding saved servers supporting personal caching and import...
2018-01-25 14:38:41.978 AssetCacheLocatorUtil[1205:33620] There is no saved result. (This is not an error.)
2018-01-25 14:38:41.978 AssetCacheLocatorUtil[1205:33620] Finding saved servers supporting shared caching...
2018-01-25 14:38:41.978 AssetCacheLocatorUtil[1205:33620] There is no saved result. (This is not an error.)
2018-01-25 14:38:41.979 AssetCacheLocatorUtil[1205:33620] Finding refreshed servers supporting personal caching...
2018-01-25 14:38:42.369 AssetCacheLocatorUtil[1205:33620] An error occurred: Error Domain=NSURLErrorDomain Code=-999 "AssetCacheLocatorService: cancelled" UserInfo={com.apple.AssetCacheLocator.tag=#ad830ae3, NSLocalizedDescription=AssetCacheLocatorService: cancelled}
2018-01-25 14:38:42.370 AssetCacheLocatorUtil[1205:33620] Finding refreshed servers supporting personal caching and import...
2018-01-25 14:38:42.374 AssetCacheLocatorUtil[1205:33620] Found 0 servers
2018-01-25 14:38:42.374 AssetCacheLocatorUtil[1205:33620] Finding refreshed servers supporting shared caching...
2018-01-25 14:38:42.375 AssetCacheLocatorUtil[1205:33620] Found 0 servers
2018-01-25 14:38:42.375 AssetCacheLocatorUtil[1205:33620] Determining configured public IP address ranges...
2018-01-25 14:38:42.376 AssetCacheLocatorUtil[1205:33620] No public IP address ranges are configured.
2018-01-25 14:38:42.376 AssetCacheLocatorUtil[1205:33620] --- Information for user 0 (results for other users may be different):
2018-01-25 14:38:42.376 AssetCacheLocatorUtil[1205:33620] Checking whether there might be caching server(s) available...
2018-01-25 14:38:42.628 AssetCacheLocatorUtil[1205:33620] There might be caching server(s) available.
2018-01-25 14:38:42.629 AssetCacheLocatorUtil[1205:33620] Finding saved servers supporting personal caching...
2018-01-25 14:38:42.631 AssetCacheLocatorUtil[1205:33620] There is no saved result. (This is not an error.)
2018-01-25 14:38:42.631 AssetCacheLocatorUtil[1205:33620] Finding saved servers supporting personal caching and import...
2018-01-25 14:38:42.632 AssetCacheLocatorUtil[1205:33620] There is no saved result. (This is not an error.)
2018-01-25 14:38:42.632 AssetCacheLocatorUtil[1205:33620] Finding saved servers supporting shared caching...
2018-01-25 14:38:42.633 AssetCacheLocatorUtil[1205:33620] There is no saved result. (This is not an error.)
2018-01-25 14:38:42.633 AssetCacheLocatorUtil[1205:33620] Finding refreshed servers supporting personal caching...
2018-01-25 14:38:42.918 AssetCacheLocatorUtil[1205:33620] Found 0 servers
2018-01-25 14:38:42.919 AssetCacheLocatorUtil[1205:33620] Finding refreshed servers supporting personal caching and import...
2018-01-25 14:38:42.919 AssetCacheLocatorUtil[1205:33620] Found 0 servers
2018-01-25 14:38:42.920 AssetCacheLocatorUtil[1205:33620] Finding refreshed servers supporting shared caching...
2018-01-25 14:38:42.924 AssetCacheLocatorUtil[1205:33620] Found 1 server
2018-01-25 14:38:42.925 AssetCacheLocatorUtil[1205:33620] 10.4.193.73:49410, rank 1, guid 7F03051D-6C27-4EC7-9957-F463C49ACEE0, valid until 2018-01-25 15:38:42; supports personal caching: no, and import: n/a, shared caching: yes
2018-01-25 14:38:42.925 AssetCacheLocatorUtil[1205:33620] Determining configured public IP address ranges...
2018-01-25 14:38:42.925 AssetCacheLocatorUtil[1205:33620] No public IP address ranges are configured.
2018-01-25 14:38:42.925 AssetCacheLocatorUtil[1205:33620] Testing all found servers for reachability...
2018-01-25 14:38:42.931 AssetCacheLocatorUtil[1205:33620] This computer is able to reach all of the above caching servers.
I have the same error as before but it found 1 server.
When I lunched App store, it loaded faster and all the images were there but when I clicked on Update I had the error message:

Thanks.
Lucas