Can't add my corporate account in the Gmail app in my Android phone

I want to add a corporate-managed email in the Gmail app, but it opens a site for authentication that has to be opened in desktop mode. On Android, it's opened in the app's internal browser and I can't switch to the desktop site and can't add the mail. However, on iPhone, it opens Safari in which I can switch to desktop mode, and the email is added successfully. The email can only be added to the Gmail app. I tried rooting my phone, deleting the Gmail app, and adding the account through Settings, but it still opens this internal browser (web view I think).