Pixelmon Mod

I am not sure whether or not this is the proper place to post this, but I believe it was after I updated my minecraft to the latest version, every time I go to start up pixelmon from the launcher it gives me the message "Library com.mojang:netty:1.6 is missing! Please press install to download it again." I do not see an install button anywhere and do not know how to fix this. If anyone knows how to help that'd be appreciated, and if I need t post this somewhere else simply let me know.

do you see that arrow in the box?click that and that should do!

I attempted to click that but for some reason it wouldn't let me. I just uninstalled the mod and reinstalled it and it works fine now.