You want to add or delete an enabled sender in the EFP portal.
Email Security.cloud
Email Fraud Protection
Enabled senders are third-party senders that you allow to send email on your behalf. You can enable senders for each registered domain and their subdomains individually.
Steps:
1. On the Configuration page, in the Enabled Senders area for the registered domain, click Enable a Sender (“+” icon).
2. Select the sender to enable from the Email service provider drop-down menu.
3. Click Enable. The sender is added to the Enabled Senders list. The sender will be configured as needed for SPF authentication. If the sender supports DKIM authentication, a warning message in the DKIM Keys area appears, prompting you to configure a DKIM key. To disable a sender, click Disable this sender? (" X " icon).