Some mkv files and some MP4 will not play on BR player

I have played many videos of many file types on my Toshiba BR player via media server from my laptop and by a usb memory stick. I moved my TV/Blu ray around and now I am unable to find all the users on my laptop when I use media server (I am not out of range) and I cannot open the files on the user that I can see. I can navigate thru the folders as before but no files appear. When I use the usb stick it says "file type not supported". I have changed files that won't play to the same as ones that do, such as MKV or MP4 but they will not play when others do.
All connections are the same, network is working, I am at a loss.

Help would be great

Abel