I have a terrible question on "play start " and i cant solve it

I am study UE4 a few weeks,this time i study how to show ui on pawn,but when i done it and run the game, my character isn’t born on the “play start” where i set 。

I only can control spectator camera,and i check bp_gamemode and Bp_character, i sure i do not open the spectators .

I also make new level , BP_gamemode ,BP_charcter in this project .i still born as spectator not my “Play start”.

I make a new project ,put new level,"Play start " BP_gamemode and character,it not have this problem.

so somebody can help and tell me why i cant born as my character in my first project?