Freebsd-update fetch Looking up update.FreeBSD.org mirrors… none found.

Today, to check updates for FreeBSD 12.1, I've execute following command:

$ sudo freebsd-update fetch

...

Then, I've received a error message:

freebsd-update fetch Looking up update.FreeBSD.org mirrors… none found.

Using some internet search engines, I've found a blog:

How to fix freebsd-update no mirror problem

https://rasyid.net/2015/12/12/how-to-fix-freebsd-update-no-mirror-problem/

This blog says:

# freebsd-update -v debug fetch

# freebsd-update -s update1.freebsd.org fetch

# freebsd-update -s update2.freebsd.org fetch

I've tried to do following commnad:

$ sudo freebsd-update fetch

...

So, the error message has gone...