Looks like the forum's JavaScript (posting.js/posting.min.js) is not loaded. There should be a whole bunch of formatting buttons, which are also not shown.

I had this after doing some mistakes in manipulating the posting.js or using bad JavaScript minifiers, which generated a corrupted minification.

It may also be, that the forum address in the forum's settings is inavild, not matching the real URL (or containing an unnecessary forward slash at the end?), causing the JavaScript files (including main.js/main.min.js and admin.js/admin.min.js) not getting loaded at all.

regards
Taurec