Hi @ABK
Thank you for posting this in Microsoft Q&A.
I understand you are trying to set up a B2B collaboration for Teams with a Chinese tenant, but you are receiving an error message saying, "access is blocked by the organization."
To set up B2B collaboration between partner organizations in different Microsoft Azure clouds, each partner mutually agrees to configure B2B collaboration with each other. In each organization, an admin completes the following steps:
1.Configures your Microsoft cloud settings to enable collaboration with the partner's cloud. 2.Uses the partner's tenant ID to find and add the partner to your organizational settings. 3.Configures inbound and outbound settings for the partner organization. The admin can either apply the default settings or configure specific settings for the partner.
After each organization completes these steps, Microsoft Entra B2B collaboration between the organizations is enabled.
Based on you provided data it seems you have completed step1 and step2, you have to complete step3.
Users from another Microsoft cloud must be invited using their user's principal name (UPN). Email as sign-in is not currently supported when collaborating with users from another Microsoft cloud.
For more information, refer to this document: https://learn.microsoft.com/en-us/entra/external-id/cross-cloud-settings
Hope this helps. Do let us know if you any further queries.
Thanks,
Navya.