Asset validation failed 90270 and 90259

Question

Our Blazor MAUI Hybrid app is in production and the other week it was working fine to upload a new version to App Store with Transporter. However, when trying this now it gives us the errors:

Asset validation failed (90270)

Unsupported toolchain. Packages submitted to the App Store must be created either through Xcode, or using the productbuild[1] tool, as described in "Submitting your Mac apps to the App Store." Packages created by other tools, including PackageMaker, are not acceptable. [SIS] (ID:...)

Asset validation failed (90259)

Bad Bundle Executable. You must include a valid CFBundleExecutable key in your bundle's information property list file. (ID: ...)

We are compiling with XCode 15.4 on macOS 14 Azure DevOps Hosted Agent. We also tried using RootNamespace as value to CFBundleExecutable by doing below in info.plist but still get the error above.

<key>CFBundleExecutable</key>

<string>Company.My.App</string>

Any suggestions on how to resolve these issues? We are stuck on how to resolve this. We have also tried with macOS 13 XCode 15.1 and we haven't made any changes to the code really. We know that there recently were new app requirements on the app store but just cannot understand how we should fix these issues.