after replaced remote key battery, it does not work. What is the problem. on 2001 Mercedes-Benz ML320

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
I did the synchronization but still not working.
(1) Answer
i had same problem went to auto zone and tested it it worked changed batteries but still not working on the truck