Yeah, this one's common. A flashing orange light on the mode button means an incompatible tool is attached.
FIX: Detach whatever tool or cleaner head you have connected. Make sure you're using a tool designed for the V8. Reattach it properly. If using the wand, it must be connected to the main body, and the tool must be attached to the wand or directly to the body. Ensure all connections click firmly into place.
IF THAT DIDN'T WORK: If the light is solid orange, that indicates a motor fault. If it's flashing white, the cyclone isn't fitted correctly. For a white light, remove the bin and cyclone, then reseat the cyclone securely in the grooves of the main body and push down until it's in position.
HEADS UP: Tools and cleaner heads can be attached either to the wand or directly to the main body. Just make sure everything is clicked in all the way.