This is a known issue as reported by Salesforce. You can try the workaround explained in the article.
Extracts from the link.
Summary
Customers may notice an error when trying to open an inline Visualforce page from the standard record detail page (or mobile card) while in a Community. This same inline Visualforce page will open as expected when in the standard Production environment.
In the Community, a preview of the Visualforce page is shown on the record detail page (i.e. mobile card), but when a user taps to open this page they may see the following error:
"You can't view this page, either because you don't have permission or because the page isn't supported on mobile devices."
Repro
1. Launch Salesforce1.
2. Open the navigation menu and switch into a Community.
3. Open any record with an inline (embedded) Visualforce page.
4. Tap on the Visualforce page preview to open the full page.
Users sees error message: "You cannot view this page, either because you don't have permission or because the page isn't supported on mobile devices."
Workaround
A text link pointing to the Visualforce page or a Detail Page Button that uses the Visualforce page as the source should open the page as expected.
Don't utilize mobile cards for VF pages needing to be interfaced via users.
Available for Salesforce mobile apps and Lightning Pages
checked for the visualforce page.