DC 3-12V Water pump connected to power source doesn't work
Your power supply does not provide enough current for the motor, it's as simple as that.

EDIT: Links to a vendor like amazon (or ebay or aliexpress) are often of little value. You should try to provide links to an actual manufacturer's data sheet. If you can't find the manufacturer's data sheet then don't buy the product. It's buried toward the bottom, but the listing for your motor does tell you how much current it needs...and not to bother trying to use a supply that provides less current.