Just tried accessing it via backend (Components -> Admin Tools), and get the following popup:
This page isn’t working
my_domain.net is currently unable to handle this request.
HTTP ERROR 500
I'm pretty sure I accessed it a few months ago, and since then, as far as I know, nothing has changed. I've certainly not done any manual updates to anything on the site.
I have just updated my 'Admin Tools' Akeeba subscription to be able to load in the latest version of Admin tools, but wary of doing anything while I have this error.