UT4 crash when flag is captured

Hello everyone,

Currently I’m working on a capture the flag map and my map is almost completed however there’s a problem, a big one. Whenever players tried to get the flag or even touch it, the whole game crashes. I don’t know what reason crashed the game, because, I tried to fix this problem by removed half of the light in my map, and also all of foliage that contained in the map, and also replaced the flag to a new flag, however nothing fixed the problem.

Please help me. I would be very much appreciate it