Uploading to the partner center, Validation error

[Vanessacs]

I am a intern for a company which I am helping them upload a package to the Microsoft store. 

The package was converted from an EXE to MSIX using the MSIX packaging tool. 

When uploading to the partner center I received this error message. 

Any help is appreciated, I am new to this :) 

[#2]

What I remember is that I used an .msixupload file for the store submission. This may be created from in visual studio. I think they moved where the menu is in 2019 version, but somewhere there is a "publish" that will create the .msixupload file.

[#3]

I looked for it and found it. In Visual Studio you now go to the Solution Explorer and pick on your project, right-click and select Publish-->Create App Packages.

[#4]

@TIMOTHY MANGAN Thank you, I will give this a go, much appreciated