To whom it may concern,

I am having the same problem as this post (https://stackoverflow.com/questions/50211669/matchit-cem-subscript-out-of-bounds-error?rq=1), receiving the following error message: 

Error in `[.default`(tmp, x, bg) : subscript out of bounds

I tried to use cem directly but still got the error message.

My dataset works fine with other matching methods, and has observations where no matching is available. 

Any suggestion would be highly appreciated! Thank you!