Video's not appearing in Color page

None of the footage I bring into the edit page is appearing in the Color page or Fusion. I've tried a few different videos from different sources and none of them appear. Any ideas whats going on? I've searched for this problem on here but I've not found a satisfactory answer yet.

But you see the videos in your timeline, do you?

yes i do.

Can you describe your hardware and your sources?

Sources are mp4 video files
Hardware is Asus Radeon RX 480 Dual OC 8192MB GDDR5 PCI-Express
Graphics Card
Custom Intel i7-7700K @ 4.2GHz System
Team Group Vulcan T-Force 16GB (2x8GB) DDR4 PC4-24000C16
3000MHz
WD Blue 500GB 2.5" SATA 6Gbps Solid State Drive