I've done a project over 4 minutes long in iClone 6.
It sounds like you covered the basics, including the "green triangles." You are talking about the ones by the scrubber, right?
Does the video PREVIEW okay? Or does that stop too?
I'm not sure what you're missing.
iClone 7... Character Creator... Substance Designer/Painter... Blender... Audacity...
Desktop (homebuilt) - Windows 10, Ryzen 9 3900x CPU, GTX 1080 GPU (8GB), 32GB RAM, Asus X570 Pro motherboard, 2TB SSD, terabytes of disk space, dual monitors.
Laptop - Windows 10, MSI GS63VR STEALTH-252, 16GB RAM, GTX 1060 (6GB), 256GB SSD and 1TB HDD