Hello, I am having the same problem with Tapatalk on iPhone and the this forum. I have sent an email to Tapatalk and received a reply.
Can you request your forum admin to update the Tapatalk plugin, he is running a rather old version.
Meanwhile, are you able to share us your id and password so we can look into the exact issue for you?
Maybe the new plugin will resolve the issue. I am a little reluctant to give out my id and password.