Can't start a new topic

I'd like to start a new topic in "Growing hot peppers", but everytime I hit "Post new topic" or "Preview post", I get redirected to the main index page of the site.
Anybody got any idea?
Ha, well, at least I'm glad I can post here  :lol: .
btw: I tried different computers, my phone and removing cookies and so on..
In the editor on the far right there's a button that you click and it says:
"Paste as plain text by default"
Check Yes and see if that helps. Thanks!
Tried that, didn't seem to work.
Then I rewrote the whole thing, instead of pasting what I wrote before, and yep! Worked!
Thanks for the swifty reply! :)
Now it's happening again, when I reply to my own topic.
I have no idea why it sometimes works, and other times not. Internet connection is stable, I selected 'paste as plain text'...
So frustrating haha