MyBB Community Forums

I've got the well-posted problem when logging in, where I get the message:
"Authorization code mismatch. Are you accessing this function correctly? Please go back and try again"

This is a fresh install of MyBB 1.8.19, with the BootBB theme installed. I've read the post at https://community.mybb.com/thread-218862.html.

It looks like indeed the required hidden inputs are missing for some templates in the "BootBB-theme.xml" file:
<input name="my_post_key" type="hidden" value="{$mybb->post_code}" />

My problem is that, since I can't log in to the Admin CP, I'm not sure how or where to add these statements. I've searched, and can't find any information on this.

Is there an upgrade/edit path for adding these required hidden inputs?

Why can't you login to the ACP? The authorization code mismatch doesn't affect that login. Just go to the ACP directly. By default it'll be domain.com/admin or wherever your forum is installed.

Thanks. Indeed, I was going via the main forum page, not directly to the admin login.