Unable to Resolve the error when using fabric workload to connect to Fabric for showing react app

Issue title for above: 

I have enabled devloper mode and 

Workspace admins can develop partner workloadsEnabled for the entire organization

Fabric DevGateway registration fails: Extension package blocked by malware scanner

Product:
Microsoft Fabric

Problem:
I am developing a Fabric workload using Fabric Extensibility Toolkit / DevGateway.
DevGateway starts successfully and receives interactive user AAD token, but registration fails with Forbidden.

Latest error:
HTTP status code: Forbidden
errorCode: UnknownError
moreDetails errorCode: SecurityValidationFailed
message: Extension package was blocked by malware scanner

Request ID:
44ae902b-809a-4d90-b5d8-7195c7ddbc61

Workspace:
96441fdc-6968-4ac6-b90c-b9905ae2d718

Package:
Org.HelloWorldWorkload.1.0.1.nupkg

Package contents:
Only required Fabric workload manifest XML/JSON files.
No binaries, no EXE, no DLL, no scripts, no node_modules, no images, no nested ZIP files.

Package files:
BE/HelloWorldItem.xml
BE/WorkloadManifest.xml
FE/HelloWorldItem.json
FE/Product.json
Org.HelloWorldWorkload.nuspec

What I already tried:
- Removed image assets
- Removed translations/assets
- Removed external URLs
- Removed NuGet metadata folder
- Changed workload name
- Rebuilt package with new version
- DevGateway authentication works, only package registration fails