When changing network password, any client apps logged in must be updated with the new password.

1. Open Nine mail for work
2. Select the 'hamburger' 3 line menu on top left of app
3. Click the settings gear on bottom right of the pullout window
4. Select your work email account
5. Double check the sync schedule is set to automatic or Peak, and not Never. 
   Never will, as name states, not sync mail unless you force manually.
6. Scroll down to Content to sync, enable anything is turned off here as you'll want to turn it on otherwise
   If items were turned off, this may be all that is required.
7. Scroll down to bottom and select Account Settings.
8. Enter your password into the field. 
   *Remember to use the 'eyeball' in field at end to view your entered password to ensure you put in what you meant to.
9. Click Save, then approve the MFA popup request.

https://www.youtube.com/watch?v=PNSp107osB8