Microsoft are ending support for the connector action "Send an email notification" and will eventually be deprecated (and therefore stop working).
If you use Power Automate to send emails, please review your flow and swap out the "Send an email notification" for an alternative:
Office 365 Outlook connector (recommended): Send an email (V2)
or Mail connector: Send an email notification (V3)
Do you use Power Automate to send Emails?