Why can't our customers unsubscribe from our mailings?
Mailings, Configuration Settings
Oracle Service Cloud
Unsubscribe button is not working in mailings from mobile network.
This message is returned when the “SEC_VALID_ENDUSER_HOSTS” configuration setting has been enabled.
Since the "Unsubscribe" link will redirect end-users to the Customer Portal page, it is expected behavior to receive "Fatal error. Access Denied. Client address is not authorized" as long as the IP address of the end-user isn't listed in the configuration setting mentioned above.
If you decided to enable “SEC_VALID_ENDUSER_HOSTS”, an alternative would be to remove the "Unsubscribe" link from your mailings and have the end-users reply back if they wish to unsubscribe. The removal of global opt-in would need to be done manually.
For more information on accessing the Configuration Editor and editing settings, refer to Answer ID 1960: Editing Configuration Settings.