A subscription will end if the Power BI Pro or Premium Per User (PPU) license expires, the report or dashboard is deleted by the owner, or the user account used to create the subscription is deleted.
To avoid subscription emails going to your spam folder, add the Power BI email alias (email@example.com) to your contacts. If you're using Microsoft Outlook, right-click the alias and select Add to Outlook contacts.
Subscriptions may fail on reports or dashboards with extremely large images due to email size limits.
Make sure that your User Principal Name (UPN) can receive emails.
Though you have a Power BI Pro or Premium Per User (PPU) license, you may not have a Microsoft Exchange license. If not, your Azure Active Directory account may not have an email or alternate email address specified. In this case, though the subscription appears to go out, you never receive a copy. If your Power BI admin assigns an email address, Power BI will synchronize the update the next time you sign in, and use that email address for the subscription.
If you have an alternate email address but no primary, Power BI uses that to deliver the subscription.
Admin portal settings
Email subscriptions are not supported when Block Public Internet Access is enabled in the Power BI admin portal.
Please troubleshoot this issue with these steps firstly and let me know whether they help. Thanks in advance!