R6260 ReadyShare HTTP cannot access files

For USB_Storage, SMB (\\readyshare) connects to and can access router's USB_Storage files from PC, phone, and Chromebook, in File Manager or AndSMB app on phone. But, cannot access files with http, https, ftp, and ftps in multiple browsers. All folders are accessible, but get a browser error message when trying to access the files within these folders. See below.

A tech support rep had me try changing DNS settings from 'Acquire DNS automatically' to 'Use these DNS addresses' and to set the Primary DNS to 8.8.8.8 and the Secondary DNS to 4.4.2.2, which broke my internet connection after clicking 'Apply' and then rebooting router, which also broke the connection to the webGUI (192.168.1.1) so couldn't set back to the previous "Acquire DNS automatically'. I didn't restart PC, which might have discovered the new DNS and then connect to internet using 8.8.8.8 as the new DNS. The rep said nothing about restarting PC after the connection was broken.

Had to perform factory reset and start from the beginning. Apparently, those DNSs are Google's and Amazon's DNS servers, lol.

Here is a portion of the browser error message at http://routerlogin.net/shares/USB_Storage/Music/Allen%20Ginsberg

X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1;mode=block
X-Content-Type-Options: nosniff
Connection: close

XSS is cross site scripting protection, which appears to block access to files on a device on my home network.

Get the same exact error message for ftp://routerlogin.net/shares/USB_Storage/Music/Allen%20Ginsberg and when using ISP provided IP address in place of 'routerlogin.net' for https and ftps.