How does Roku figure into this? Are you using a Roku TV? If so, Roku doesn't make the hardware, only the software for the "smarts" of the smart TV. You should probably reach out to the manufacturer of the device.
Having said that, you've got three parts to figure out if they're working properly.
Laptop HDMI port
TV HDMI port
For the first item, try it on another TV or monitor. If it doesn't work, that leans toward the laptop HDMI port being bad.
For the second, try a different device into that port. If the other device works, it's not the TV HDMI port.
For the third, try a different cord.
For further, you'd have to get the results of those tests and calculate the next steps, focusing on what is still possible as the problem.
DBDukes http://www.dbdukes.com/Roku Ultra (4660) Roku Streambar (9102) Roku Streaming Stick+ (3810)
On some laptops the HDMI port can be enabled/disabled. I've also seen laptops where the HDMI port, by default at least, displays whatever resolution/format is on the laptop screen, and that isn't always a standard TV format.