Can't launch a Session

I had a problem with launching a session and I had quit out thinking it would fix itself and and I went back to launch a session i still can’t it says this “LogValkyrieValidation: Error: [16] Found disallowed object type /Game/Balance/Physics/Materials/PhysData_Foliage.PhysData_Foliage” How do I delete this thing so I can launch a session or fix it

Also somthing to note was before I had my game open in fortnite in it and UEFN and I had placed a Prop mover in fortnite in it and I didn’t see it in UEFN and I then placed one in UEFN and didn’t see it in my fortnite perspective and I had pushed changes both times then I deleted them then later when I went to run game again it didn’t let me