Introduction
This morning I bummed into “To open the web app, you need to change your browser settings to allow third-party cookies.”

Haven’t had issues with login into teams on my browser before. So, this changed during the weekend.
Why use Teams on the browser in the first place?
Well I am working with a customer right know and they created guest access for me, so in order to not change organization in the thick Teams client, I use the web browser to have two separate sessions running at the same time.
Requirements
- Microsoft endpoint manager
Add policy to let people access teams again
Open https://endpoint.microsoft.com/
Devices -> Windows -> Configuration profiles
Create profile


Good naming standards are preferably
Search for Allow cookies on specific sites


You could add wildcard, but I like to be sure what is allowed and what does not.

Deploy it to the group of device or users that need to get the policy

Create
Sync your devices
Summary
If you have disabled third-party cookies which you should, then you will sometimes see these screens. It’s good to have an aligned method to enable sites, your company needs to access.
Happy testing!