Audio out of sync or goes silent when exporting

I've read a lot of the posts but don't seem to find an answer that work for me so I'm trying again.  Have the new Macbook Pro all fitted out.  I'm going to put the screen grab of how I'm exporting.  The video is 75 mins file is 24GBs editng is just into and outro.  Latest version of Premiere.  Here are my export settings. 

Thanks in advance.