I had the same issue (with Admob I had black screen. Without was fine)
It was an issue with the version of C3 I was using, I think the issue was with r69. I'm using r73 atm and it's fine.
if that hasn't sorted it, I'm not sure, but try using r71 which is the only 'stable' version https://www.construct.net/gb/make-games/releases
And if it's still not working, then when exporting DONT 'minify script'.