PowerBI Report + OOS: Excel with AS works, but Excel with PowerPivot fail

Dear Masters,

We setup PowerBI Report Server(15.0.1102.235) and Office Online Server(OOS) is one server, also intsall 2 SSAS instances(SQL2012), one for tabluar model, another for PowerPivot mode in same server. We uploaded 2 excel files to PBIRS, ones' source cnnected to SSAS tabular model, it could work well, like add/move dimension. But another file with PowerPivot, it can be open, when we add dimension into Pivot table, error message prompted: 

We cannot locate a server to load the workbook Data Model.

It look seems OOS cannot connect to SSAS PowerPivot mode, we check log file, here is error message:

Checking Server Configuration (twtpewgdwdb02d\POWERPIVOT) ...
05/09/2019 11:06:46.53 w3wp.exe (0x20DC) 0x4A88 Excel Online Data Model sql01 Medium --> Check Administrator Access (twtpewgdwdb02d\POWERPIVOT): Pass.
Check Server Version (twtpewgdwdb02d\POWERPIVOT): Pass (14.0.1.278 >= 11.0.2800.0).
Check Deployment Mode (twtpewgdwdb02d\POWERPIVOT): Pass.
Check Server Configuration (twtpewgdwdb02d\POWERPIVOT): Pass.

SSPM: Initialization failed on server twtpewgdwdb02d\POWERPIVOT: Microsoft.AnalysisServices.AdomdClient.AdomdErrorResponseException: The '\MSOLAP$POWERPIVOT:Memory\Memory Limit High KB' performance counter could not be found.

Refer https://docs.microsoft.com/en-us/sharepoint/support/experts-admin/powerpivot-performance-counter-errors,  there is no "Disable Performance Counters" in system registry, so...we add manually, but still not fix the error.

Finally, follow isstruction, we try to re-create the performance counter, run below command:

unlodctr msolap$pwerpivot

Error message prompt:

Unable to open driver SYSTEM\CurrentControlSet\Services\msolap.

Is anything wrong or any suggestion?

Many thank!