I haven’t released anything with unreal engine 4 yet so I don’t know, sadly. It’s definitely a false positive like franktech says though (as you created the game yourself, you already know it’s not a virus, and usually signing is the last step, such as when the game/project is finished.
Honestly, it sounds like someone made a malicious unreal engine 4 game/Malware before, and the virus software are just flagging unreal engine programs no matter what they are, thanks to the one bad program. If that’s the case, then there is nothing you can do. In that situation, most people are willing to allow a game through firewall/antivirus after release. It’s a common problem on steam, if I recall.