Hi @Mo-PHAT ,
For guest user sharing. The following prerequisites must be met in order to share with external users.
- The ability to share content with external users must be enabled
- Guest users must have the appropriate permissions to view the shared content
Also, have you checked the setting of your admin portal?
For more details, you can read below document:
Distribute content to external guest users with Azure AD B2B - Power BI | Microsoft Learn
If the problem is still not resolved, please provide detailed error information and let me know immediately. Looking forward to your reply.
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.