No success with NFS on my oled55b9. So I solved the problem by using DLNA. I installed minidlna packet on my Debian/Jessie and now I can share my music/video/image without problem. I just regret that the FLAC files (music) are not compatible with webos4.5 Maybe this can help other people.
I just bought the oled55b9pla and found that my nfs share was inaccessible! With my Sony I bought in 2008 nfs was not a problem at all. I never thought this could be an issue in 2019 with a SMART TV. Not so smart after all.