You may run into this error code due to a network connection issue preventing you from being able to authenticate. You can see if this error is happening by reviewing your Epic Games Launcher log files. For more information on how to locate these click here.
Below is an example from a log file suffering from this error. It reveals that the player is unable to connect due to an SSL timeout resulting in a server connection failure:
Often times a background application causes this error due to blocking your connection. Make sure to disable all your background applications as outlined here and then try again.
Make sure to go through all of our network connection fixes should assist you in resolving this error code here.
Let us know how we can help you.