Outlook mail not syncing anymore in my HTC 8X WP 8.1

[TheBluesOne]

Hi Guys, I'm using HTC 8X WP 8.1. Last Thursday (20/Oct) when I turned on my home WiFi to check emails. Outlook email said "Email is up to date". The following Friday, when I opened the Outlook app, on top it says "Last updated last Thursday". I manually synced Outlook, but it keeps syncing and doesn't update my emails. The same happened with Gmail. I deleted Gmail account, added again and sync issue got resolved. But I'm unable to delete Outlook mail. I logged into Outlook Web mail and all is fine. I checked for solutions in MS website, but they are of 2012 and are not useful. Can anyone suggest a solution or a workaround please. I did not change my Outlook password. The only change is my SIM got upgraded from 3G to 4G.

 

[TheBluesOne]

I don't know what had happened, why it happened. As of today Friday morning, my Outlook mail started syncing as it should.