Is ActivityPub Pinging Not Working‽

For some reason ActivityPub stopped working on my account. My website is https://darnell.day & on the Fediverse it appears as @darnell@darnell.day (when viewed on Mastodon, Misskey, etcetera).

I am wondering if this is a random bug on my site or something that is happening across the platform.

It is working again! I am not sure what happened, but after a day the federation has returned. Yay!

Hmm, very strange… How was it broken, were you unable to find it when searching? Or posts not showing up in your feed?

Basically it was no longer pinging accounts when I mentioned user handles. I am not sure why. I think it was a random bug. It started working again after I updated some customization changes in the settings.