@Abdu77 Like said above, install Emoji's extended, and for the 502 error, consult Leet since your forum isn't hosted at NodeBB, keep in mind that NodeBB requires some technical skills to keep online.
Nobebb forum + Firefox + Tree Style Tabs
I've been using Tree Style Tabs as an add-on with FF for around 5 years now. Starting a few weeks ago I noticed that FF is just flaky as ever whenever I have Mangolassi open in a tab. ML itself often gives scripting timeout errors, etc, but it causes all of the open tabs to hang constantly (FF title bar will say Not responding frequently).
In an effort to see what my problem was I looked at my add-ons and the only slightly unusual things I have are Lastpass and Tree Style Tabs. So I removed Tree Style Tabs first. Since then things have been working fine.
Anyone else using this add-on?
If not, anyone else willing to install it and see how things behave for them?