Diagnosis
New unit smell or taste transfer from the water source or a dirty water system.
How to Fix It
For a new unit, run several cycles with a 50/50 vinegar-water mix and dump the ice, then run several cycles with fresh water. Always use filtered or bottled water, not hard tap water. Regularly clean the water reservoir and air filter (if equipped) with mild soap and water.
If That Didn't Work
The taste might be from the water line itself. Try a different water source to rule that out.
Heads Up
The plastic taste usually fades after the first few thorough cleaning cycles. Storing ice long-term in the basket can also pick up odors from the surrounding environment.