The Client/Secret is generated within Artifactory when a new Sumo Logic account is created via that integration and therefore you can't use the access id/key generated in the Sumo Logic account.
The 10-minute mark of the webinar in this link shows how this Client/Secret gets generated with the account creation.
If you have any issues with Client ID and Password, contact JFrog Support.
On another note, If you want to integrate an existing Sumo Logic Account with JFrog, it is currently not possible. You have to use JFrog to create a Free Sumo Logic Account.
For more information, please go to JFrog Artifactory Sumo Logic Integration.