Try restarting your PC and try again. You may also check your Firewall settings and, if possible, switch off the Firewall and test if it works offline, that is, if users no longer having the error message when the firewall is offline.
If it works, then you may want to turn the Firewall back on, and if the error persists, your IT will need to investigate the Firewall setting issues and resolve the issue from their end or try using other laptops or computers.