I’m so frustrated that all these threads on this topic end like this. I have had this problem for two weeks, and have tried everything suggested with no solution. Finally tonight I uninstalled UE4 and then re-downloaded it and re-installed it. This made things infinitely worse as now I can’t just sign in, but I can’t even work off-line because it deleted all working versions of the engine I had before, and I have no way of re-installing them without signing in. This having to sign in version of UE4 is frustrating in itself, but not being able to and faced with this problem is the worst thing. I have a deadline in one week, and ZERO way to work on my project thanks to this problem. I don’t want vague solutions, or voodoo like turning on and off my computer. This needs to be addressed.