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Hi Kishan,
Thanks for posting back.
I have tested it on my end (iPhone's Safari) and it works fine. To my knowledge, there is no Microsoft 365 policy/setting that can restrict user accessing SharePoint in a specific browser on mobile devices. In this case, I suggest you report the problem to your tenant admin or IT team and ask them to raise a support ticket via the Microsoft 365 Admin Center> Support> New service request. The support team there has the correct channel and resources to help you investigate more and find what exactly reason has caused this problem at the backend.
Sorry for the inconvenience that happened to you. Appreciate your understanding and patience.
Sincerely,
George | Microsoft Community Moderator