Tapatalk should work again, if not remove the forum from your list and search "Red Impact" and add it again.
What is tapatalk?
Tapatalk is an app for iOS and Android, which you can use the browse and post in the forum, without much loading of the template. It optimizes the forum for your smartphone.
Just search the app on the store/marketplace.
You don't(!) need a tapatalk account to use everything, once you are connected to the forum, you can just login with your account details from the forum and post.