There are several issues that can keep you from being able to sign into Office 365 properly and allow you to edit documents.
First and foremost make sure that you downloaded your copy of Office 365 from SUNY New Paltz and not another organization. In the past we have had issues where a previous institutions O365 instance would fail to accept a New Paltz log in and Office had to be uninstalled then reinstalled with our version which worked without issue. If your installation is from a previous school or job this could be the issue but only uninstall after going through the rest of the steps.
Second we want to make sure you are using your Office365 account and not your hawkmail account. You will want to be signing in as <you username here>@newpaltz.edu and you can use the same password that you use for my.newpaltz.edu
If those are both in correct and in place let's take a look at the following steps
Verify that you are using the proper account:
Click "Use Another Account" and sign in with your email address and Microsoft password
Alternately, click the "Activate" button and sign in with credentials.
If that does not work, you can attempt to clear credential caches and reactivate office 2016 for the Mac:
Quit out of Office completely
Open finder → click go on the top menu bar → go to folder → input the following path: ~/library/Group Containers/
Right-click each of the folders below if present, and then click move to trash (please be certain that it is only these three folders you remove and not anything else)
ubf8t346g9.ms
ubf8t346g9.office
ubf8t346g9.officeosfwebhost
After that try opening Office and see if you can sign in.
If that doesn’t work the last option is to try uninstalling office for mac completely then re-install and re-activating office. Here is an article with some instructions on how to download and install
https://newpaltz.teamdynamix.com/TDClient/1905/Portal/KB/ArticleDet?ID=34400
https://newpaltz.teamdynamix.com/TDClient/1905/Portal/KB/ArticleDet?ID=111789