Okay, so here is a couple of things to try.
First, in the Launcher > Library > under the Engine version choose ‘Verify’. Once it finishes, try opening the Editor again.
If that doesn’t work, go into your antivirus/firewall and disable it. Then try opening the Editor again. If this works, then you only need to add exceptions for the Editor and maybe even the Swarm Agent.
If neither of these work, let me know.