Plex HTML5 player does not play videos
Plex web doesn't play any videos with HTML5 player enabled. Flash player seems to work fine. Vivaldi 1.0.418.3 (Developer Build) (64-bit)
It seems HTML5 player plays just few formats mp4, flv. Could not play AVI/mkv/wmv. All of them worked on Chrome and Opera.
Vivaldi 1.0.435.26 (Developer Build) (64-bit)
Mac OS X 10.11.4
That may be this unfixed Vivaldi bug: VB-14762 "Google Play Music and Plex not playing media"