Hi
I have been experiencing the same problem for over a couple of years now, and playing with the settings and various firmware updates on the TV and router just don't help
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Basically Samsung Smart TV is able to show and stream the contents from any other DLNA server (Windows PC, Android phone, etc.). On the other hand, media files shared on DIR-645 USB port are accessible by all other clients. It's just the Smart TV and the router that don't like each other
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Any input would be appreciated.
Ali