Azure login to multi-tenant AD app failing

I have user A in tenant A and a multi-tenant AD app B in tenant B. I am trying to get token from user A's context for the AD app

https://login.microsoftonline.com/common/oauth2/v2.0/authorize?client_id=a573ddda-b34a-4206-a73b-d67ff6e98aec&response_type=token&redirect_uri=http%3A%2F%2Flocalhost%2Fmyapp%2F&scope=a573ddda-b34a-4206-a73b-d67ff6e98aec%2F.default&response_mode=fragment&state=12345&nonce=678910

I logged in using user A's credentials and got error

AADSTS700016: Application with identifier 'a573ddda-b34a-4206-a73b-d67ff6e98aec' was not found in the directory 'domainA.onmicrosoft.com'. This can happen if the application has not been installed by the administrator of the tenant or consented to by any user in the tenant. You may have sent your authentication request to the wrong tenant.

I have configured AD app B with id - a573ddda-b34a-4206-a73b-d67ff6e98aec to be multi-tenant. Any idea why this might not be working?

I had the same error caused by completely different factors: I configured the Oauth2 client using Secret ID and Secret Value instead of App ID and Secret Value.

It took few hours browsing tons of config pages to figure out that the reason is stupidly simple and responses from MS API are useless.