The power bank seems defective.

Use the 2-in-1 cable provided in the package to work with the scanner and the power bank, and observe if the indicator light of the scanner turns green.

If not, try another power source, such as a phone charger/adapter. If other power sources make it work, the power bank is defective.
https://support.revopoint3d.com/hc/en-us/articles/7940054669595-What-is-the-2-in-1-cable-for-How-does-it-work-with-the-Power-Bank

If the other power source doesn't work either, the cable is defective, please try the 2-meter-long cable provided in the package instead to confirm this. 

Note: The POP scanner doesn't include a 2-in-1 cable.