You may need to switch accounts of your Site mailer Plugin. For instance, if you transfer the site to a new owner.
Note
This option is not available for Elementor One users due to how One System works
To switch Site Mailer accounts:
Navigate to your WordPress dashboard and select Elementor > Email Deliverability from the left-hand menu.
Locate the account widget in the bottom-left corner of the Email Deliverability screen.
Click on the arrow beside current plan to open the account management menu.
Select Switch account from the list of options in the pop-up menu.
Follow the on-screen prompts to log in or connect to the new account.