oAuth not working in Teams

Hi,

We are currently trying to figure out why oAuth has stopped working for our Bot in Teams.  We went back to the javascript_nodejs botbuilder-sample 46.teams-auth and deployed the code to a custom Bot in our Tenant.

In Web Chat, the sample is working.  We get a welcome message and the oAuth card when we type in 'hi'.

Clicking on "Sign In" opens a new tab on the browser, where we were asked to login and then grant consent.

Once we click on Allow, we are presented a validation code, which we can enter in the Web Chat and get a successful sign in.

In Teams, however, we get the oAuth prompt card, but the SignIn button gives the following error

Based on https://docs.microsoft.com/en-us/azure/bot-service/bot-builder-authentication?view=azure-bot-service-4.0&tabs=userassigned%2Caadv2%2Ccsharpand https://docs.microsoft.com/en-us/microsoftteams/platform/bots/how-to/authentication/add-authentication?tabs=dotnet%2Cdotnet-sample, it is said that the "Sign In" button won't work if the related Teams App Manifest does not have token.botframework.com in validDomains

However, our manifest is already carrying the required value.

We have also seen the techcommunity post at https://techcommunity.microsoft.com/t5/teams-developer/in-which-scenario-quot-webapplicationinfo-quot-nad-quot/m-p/3262237 where oAuth is working without validDomains being configured.  

Does anyone have any idea why oAuth is not working for us?

Thank You