HELP! Video is exporting but is not playing the whole Video. Exported with H.264 and Youtube 1080

and your source properties and sequence settings are important.  by any chance are any of your sources from a screen capture or smartphone?  If so, the problem is probably that they're variable frame rate. 
use mediainfo to determine whether your source is variable or constant frame rate
https://mediaarea.net/en/MediaInfo/Download
if it's variable use handbrake to convert to constant frame rate
https://handbrake.fr
and here's a tutorial on how to use handbrake
https://www.youtube.com/watch?time_continue=34&v=xlvxgVREX-Y

Please insert your screenshots into your posts so that we don't have to download unknown files. Thanks.