If you have already downloaded and are using Epic Online Services SDK version 1.15.2 and your game utilizes P2P, you are strongly encouraged to update to the 1.15.2.1 version of the SDK as soon as possible.
RELEASE NOTES
P2P
Bug Fix: Resolved a new issue in 1.15.2 where a P2P connection to a peer would timeout shortly after connecting under specific circumstances.