How can I make my exchange services work so my emails will update?

[AC Question]

I read a couple of solutions to disable exchange services but I couldn't really find where they were referring to in the apps. I didn't find any reference to exchange services.
I have an Insignia 10.1 Android tablet. My emails used to update as they came in but they haven't since about mid-Feb. Now I keep getting a message about exchange services no longer working. Can anyone advise me? Keep in mind my computer/tablet iunderstanding is mediocre to moderate.