MyBB Community Forums

Uh, okay, so 1.8.4 was released in February 2015, so 7 years ago. The current PHP version back then was 5.6, PHP 7.0 didn’t exist. However from your screenshot, you’re using PHP 7.4. I guess your host updated it. I don’t know how or why you haven’t upgraded the site for 7 years, and am honestly surprised it’s running at all on PHP 7.4, so you either need to downgrade PHP back to 5.6 (not recommended), or upgrade the forum. You're 22 security patches behind, plus countless bug fixes. You need to maintain the forum and keep it updated.

Thanks i will try that i didnt update it because i think i need to edit fix theme also though i will try and inform you accordingly.

You will need to make probably quite large changes to the theme, but that's just part of maintaining a forum. You definitely can't stay on a 7 year old version to avoid updating the theme.

I did everything is ok.