Hi @Nishad Mahajan
According to official documentation: To ensure that customers and users can treat everything under the *.cloud.microsoft domain as fully trusted, the entire domain hierarchy is isolated, purpose built, and dedicated to hosting only secure and compliant Microsoft product experiences. The domain is managed to the highest standards of domain security and reputation, and is kept free of scenarios such as third-party websites, IaaS/PaaS resources (such as file and blob storage), and hosting of active content, code or scripts that may affect the trust and integrity of products and applications residing in the domain.
So the inability to open custom apps on *.cloud may be due to security considerations.
The document also explains: Microsoft.com will continue to be used for non-product experiences such as marketing, support, and e-commerce. Only authenticated, user-facing product experiences will be hosted on cloud.microsoft.
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