Error 500 when accessing the /admin/tools/scheduler page

Hello, colleagues!

At some point, when I go to the /admin/tools/scheduler page, I started getting Error 500.
Not on one site, but on all of them.
What could be the matter?
What additional information should I provide?

Thank you!

P. S. I checked permissions in folders and files.
Everything is installed via Linux on the www-data user and the necessary permissions:

sudo chown -R www-data:www-data /var/www/${MY_DOMAIN}
sudo chmod -R a=r,u+w,a+X /var/www/${MY_DOMAIN}
sudo chmod -R a=rx,u+wx,go+x /var/www/${MY_DOMAIN}/public/bin/*

Doesn’t sound like permissions issue. Did you update Grav admin? Or maybe something on server changed?

Sure, all of plugins are updated, incl. Admin, and Grav is the last updated version too.
I’m completely at a loss…

As for the server, and I have a Caddy, I don’t even know which way to look.
I understand it roughly, but I have not made any significant changes. Although with your reply, I will now intentionally look at it!

The question remains open for now. I will be glad to have any additional ideas!

hm, I’m just experimenting with Caddy for because its easy reverse proxy feature, and found it quite good for this purpose, but, also saw that it is quite different to apache or nginx, so there might be some problems w.r. running a Grav site on Caddy.
you could check caddy-php and experiment with php versions to see if this solves your problem.
just a wild guess…