There is an extra beat in the song (both versions in the links above).

If you don't have that extra beat in there, that could be part of why you can't
get it to sound right.

An extra half measure is not unusual in bluegrass, and shows up in country music also.
In 2/4 time, this single beat would be an extra half measure.

Not sure though what the intended time signature is for this song. I hear it as 2/4.

If you could post the chords you are using where one part ends and the next part begins,
I think I can show you exactly where the extra beat is.