Sorry for the service interruptions in the last few hours. I've been notified of a new Mastodon version I better install.

Turned out I should have upgraded from 4.5.8 to 4.5.18. Since last update, versions 4.6 and 4.7 have been released. Thus I upgraded to the latest version 4.7.2 containing all the fixes 4.5.18 provides. And features!