When importing an SQL Server asset via agentless in Control Compliance Suite you see the following errors in the console.
Message shows "SQL Data Collector: query returned with message(s)."
Details shows "The operation completed successfully"
When looking in the logs you might see something similar to the following.
<messages>
<message level="2"><desc><![CDATA[[<Server1>] : Could not determine the status of SQL browser service. Please verify if windows credentials are configured.]]></desc></message>
<message level="0"><desc><![CDATA[The operation completed successfully. ]]></desc></message>
<message level="2">No records matched the query specified.</message>
</messages>
The configured SQL credential is not in the local administrators group.
When looking at the documentation it shows "Windows user credential".
Privileges to import a SQL Server Asset
However that should really say "SQL user credential"
Once you get the SQL credential added to the local administrators group on the target SQL server, the SQL Server assets will be imported.