error - cannot display the data because Power BI can't determine the relationship between 2 or more

Hello fabric_no1 

Your model doesn’t follow a conventional star schema pattern because both Product and Department (dimension tables) contain foreign keys (cust_sk) to the Customer dimension
• This creates a snowflake-like structure that can cause filter propagation issues and relationship ambiguity

Dimension tables should not typically contain foreign keys to other dimension tables
• The presence of cust_sk in Product and Department tables creates potentially confusing relationship paths

Few best practices;

Best Practices for Dimensional Modeling in Power BI
Fact Tables
• Should contain foreign keys to dimension tables and measurable metrics
• Typically have the largest number of rows in the model
• Consider incremental refresh for large fact tables
Dimension Tables
• Should contain a unique key and descriptive attributes
• Should be denormalized when possible to improve query performance
• Avoid snowflake dimensions unless absolutely necessary