Windows “Mail & Calendar” app – Not Syncing, sending, receiving or downloading

Issue: 

My Mail & Calendar app on Windows 10 is no longer communicating with my Office 365 account. This means that I am unable to:

• Send emails
• Receive emails
• Download old emails
• Download my calendars
• Make new calendar entries

Interestingly there is still a "folder" in both mail & calendar for my 365 Account, but both are inaccessible. 

I know this isn't an account or a password issue because I can still log-in via the web-office and my native "Outlook" client.

What I've tried to far:

1. Restarting the computer
2. Re-syncing the Mail app
3. Removing the account and logging in again (this deleted all the emails I already had downloaded, and did nothing to fix my issue).

Please note that this issue does not affect Office 365 online, nor with Outlook (web-office or desktop).

I've been having this issue since the most recent update for the Mailing app went live on August first

I'm at my wits end, and would very much appreciate some aid and advice

Thanks!