Need Help...

I've been using Discordapp for quite a sometime. Of late, I have noticed that I am not able to use Discordapp. Whenever I am trying to post a link in #upvote box, the message displays inside the box is "You do not have permission to send messages in this channel."

Could anyone of you out there point out the real problem and help me out by giving a proper way out??

Thnx in advance for your kind consideration to help me out...