Started a forum - it won't let me post to it

I registered a new account on my Friendica node, and selected the account type as "public forum".

I then logged in with my main account, sent the forum account a friend request (which it accepted).

Then I tried to post on the forum with my main account, but there was no button for posting with? (the button with the pen in it)

I had already made sure the forum account's setting for friends posting on your wall was switched on, and also that we were friends, so I don't understand why it won't let me post to the forum.

Have I done something wrong, or is there some kind of delay with the posting being activated?