Salesforce now requires that the Connected App be installed by a system administrator before users can self-authorize.


This ensures that the connected app (in this case, Metadata Search) is trusted and properly authorized within your Salesforce org.


Please complete the Authorize step in the  Metadata Search Configuration Guide, and then follow the steps below:

Steps to install the Connected App OAuth:

  1. Go to Setup → Connected App OAuth Usage

  2. Locate “Metadata Search” in the list

  3. Click Install next to it

  4. On the next page, click Install again to complete the setup