Are there new security measures for logging in?

They must be changing things again and not letting anybody know. Everything was going fine since January, after I had to toggle our settings again, until about maybe 5 days ago. Are there any known bugs?

I'm using Outlook from Office 365. Cannot connect to servers, again... I DO have two-step authentication turned off, and I also DO have the 3rd party setting checked.  

Thank you.