Accam was a member of the 2015 edition but was surprisingly overlooked in the provisional squad despite his incredible performance in Major League Soccer last season.
The 26-year-old was adjudged Chicago Fire's Most Valuable Player in 2016 for the second year running, after hitting nine goals in 26 appearances.
"I was disappointed when I got the news that I was not part of Ghana's final squad for the Africa Cup of Nations,'' Accam told Starr FM.
"I was very optimistic of getting a call-up into squad for the tournament as I worked very hard last season but it didn't happen as expected. I just have to keep my cool and support the team to win the trophy for us,'' he added.
Ghana were runners-up in the previous edition and have been housed in Group D alongside Egypt, Uganda and Mali to be based in Port-Gentil.
The Black Stars will leave for Gabon on Saturday after a 12-day camping in Dubai.