I have been getting this issue for some time now and finally took time to take a look on it.

Here is the case: I have upgraded my SharePoint platform from 2010 to 2013 by deploying a full new server and performing the data migration using the database detach/attach method as I don’t have any customization.

Everything went fine and sites have been migrated and working without any issue… except I then discover that user using a mobile web browser (or when the setting of their browser on their mobile device was set to MOBILE instead of DEKSTOP) always got the “classic” mobile view access error page

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This was strange has the mobile view features have been enabled, it has been working before the migration, and another sub site created AFTER the migration to 2013 is not getting this error.

It appears that there was an error in the PermMask permission for the Comments list.

The PermMask for this list was set to EmptyMask while it should have been set to ViewListItems, ViewVersions, ViewFormPages, Open, ViewPages, UseClientIntegration

Thanks to SharePoint Manager I was able to set the correct setting for the PermMask by setting the 200769 value for the AnonymousPermMask (not the AnonymousPermMask64)

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