Apple Business Manager

We are a government organization. There is a need to distribute a custom app. So we are trying to register for Apple Business Manager. But enrollment is showing error that 'D-U-S-N' number is required. And on apple developer website it has written D-U-S-N number is optional for Government organization. How can we proceed without D-U-S-N Number?

Does any from Apple check this questions ?? Also need to register account for local government institution (organization)

Apple Business Manager
 
 
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