Inability to add bibliography and numbered citations- X9, Mac OS and MS word 2016; ver 16.17

Hello,

I am struggling to get the required output style (numbered supercript, NEJM) in my work despite ensuring that output style is correct and instant formatting is on).

I am persistently getting references as non-numbered, seen as {Marcus, 2010 #15} and bibliography at the bottom of word document is not showing up.

Few things i read and tried:

The instant formatting is on

Updated my cite while you write,

updating and going back to previous verion of MS word,

Uninstalling both endnote and MS office, restarting and reinstalling

Will really appreciate some help. Thanks