Timeout Error: The report query exceeded the 225-second timeout limit in Power BI Service

While it is possible to modify the timeout on Premium and Fabric capacities you will want to think about the user experience. Do you really want to let the user wait 225 seconds for the visuals to rerender?  A generally agreed limit for acceptable UX is five seconds - all visuals should have rerendered within five seconds.  Anything beyond that will start to annoy users.

Hi naveenanda_vam,

Thank you for reaching out to the Microsoft Fabric community forum.

I understand you're experiencing a timeout error when creating subscriptions in Power BI Service. Here are some insights and potential solutions:

• The 225-second timeout limit is a known constraint in Power BI Service. Unfortunately, this limit cannot be increased at the service level. There is no difference in the timeout limit between Power BI Premium and Premium Per User (PPU) licenses. Both have the same timeout constraints. You can find more information about the features and limitations of Premium Per User (PPU) here: Power BI Premium Per User - Microsoft Learn 
• Since live reports are working fine, the issue might be related to the complexity of the queries, or the volume of data being processed during the subscription creation. Simplify your data models and reduce the volume of data being queried. Review and optimize your DAX calculations to ensure they are efficient and reduce the complexity of visuals in your reports.

If you encounter errors while creating subscriptions, you can refer to the troubleshooting guide for Power BI subscriptions: Troubleshooting Power BI Subscriptions 

If this helps, then please Accept it as a solution and dropping a "Kudos" so other members can find it more easily.
Thank you.