You must add "[URL to add]" to your remote site list to be able to create or delete a search page...
To whitelist the host of your Salesforce organization
- Log in to your Salesforce organization with an administrator account.
- Add your Salesforce organization host as a Remote Site (see Adding Remote Site Settings).
- In the Remote Site Edit page:
- In the Remote Site Name box, enter a descriptive name of your choice (without spaces).
- In the Remote Site URL box, enter the URL of your Salesforce host, as reported in the message.
- Click Save.