Starting 1st September 2022, discord made an update which disallowed verified bot to read messages.
What does this mean? Lockout bot cannot see commands you typed like .match challenge
.round challenge
etc and hence cannot reply to your messages.
Discord wants every verified bot to move from prefix based commands to their new feature of slash commands. More details here https://support-dev.discord.com/hc/en-us/articles/4404772028055-Message-Content-Privileged-Intent-FAQ
Unfortunately to migrate lockout bot to slash commands would mean rewriting the whole codebase again for which I don't have enough time at the moment.
There are workarounds to still use the bot which are mentioned below. You can also host your own instance of the bot by following the instructions mentioned here https://github.com/pseudocoder10/Lockout-Bot/wiki/Setup. Having your own instance would work completely fine since the restrictions are for bots with > 100 servers.