Video won't play in edit tab

The video will not play when I press play in the video tab (or press space) it worked last time I used it. Audio playback works in the fairlight tab but not in edit. I have updated resolve and checked my Bios but that was up to date, the problem prevails. After I restarted (to check bios) it worked initially but then stopped, I think this was after alt+tabbing to another window, if there is a keybind that would lock this then maybe that broke it? I can still move the scrubber along but cannot hear audio and the video won't show. Any help is appreciated.

There's not much info for us to go on. Give the following a good read.

viewtopic.php?f=21&t=90190