If the option to delete your forwarding address is grayed out, this likely indicates that your account requires reverification.
This situation occurs when you have an outdated USPS Form 1583 on file. To comply with USPS regulations and avoid delays in receiving mail, your account must be reverified using the updated USPS Form 1583.
For steps in completing the reverification you may follow this article: USPS 1583 Reverification
As part of the reverification process, one of your forwarding addresses will also be verified to streamline your account and prevent multiple transactions.
Once your account has been successfully reverified, you will regain the option to delete forwarding addresses as needed.
Steps to Delete a Forwarding Address
Log in to your portal.
Navigate to Settings > Forwarding Addresses.
Click on the address label you wish to delete.
Scroll down and click Delete.
Confirm by clicking OK.