@amcqinps
Yes, you can use a wall adapter with your Streaming Stick. If one did not come with your device, you can use a cell phone USB charging adapter. (5volt, 1 amp).
Post back your Roku model number and exact details (or screenshot) of what is going on. A "No Signal" could definitely be caused by an underpowered device so good initial troubleshooting step is to try the wall adapter like you are thinking.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102