This error means Battle.net Agent (the process that installs and patches our games) couldn't stream necessary files.
What to do if you have not received a Prime Gaming reward in your Battle.net account
What to do if you earned Twitch drops in the wrong Battle.net account
Troubleshooting missing Hearthstone Recruit a Friend Rewards including packs and Morgl the Oracle Hero Portrait.
Information about the Hearthstone Ranked Mode reward system
What to do if you earned a Prime Gaming reward in the wrong Battle.net account
Troubleshooting steps for connection problems
How to resolve this problem when downloading an update