most of the time it is just as the message says : clientId or clientSecret are invalid
-> double check you did not copied an extra space in one of both fields (use the copy button in the CSSM, not <ctrl+c>)
in addition check version compatibility of DNA vs CSSM version
as the device is recently installed, you may need to wait for the "new version available" message
or use software management to actively search for the upgrade(s)
also check the logs on the CSSM if this confirms DNA tries to access but is using invalid credentials