The problem is, I'm not seeing any errors. When I click on the button, nothing happens. This happens in both Safari Version 13.0.5 (15608.5.11) and Chrome Version 80.0.3987.132 (Official Build) (64-bit). I even have the Developer Toolbar enabled in Safari and Developer Mode enabled in Chrome.

The Stovebolt Geek
https://www.stovebolt.com/ubbthreads/ubbthreads.php

Server Information
UBB.threads Version 7.7.5
Release 20201027
Server OS Linux
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Web Server Apache/2.4.6
PHP Version 7.4.33
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Database Size 1.85 GB