Make sure that the file name locally has a _TB in it. Like MyVideo_TB_360.mp4 Note the underlines. That should make it work. Other VR players honor a more-or-less similar scheme.
I wish the manufacturers could just embed this information as Headers within the files themselves.
Outside of using this file name "suffix," you can use server-side options, which may be beyond your desire and scope. See
https://deovr.com/app/doc