Only platforms with Tier 1 support can be upgraded by freebsd-update.

[iceblood]

This may be because upgrading from this platform (amd64)
or release (RELEASE-13.0) is unsupported by freebsd-update. Only
platforms with Tier 1 support can be upgraded by freebsd-update.
See https://www.freebsd.org/platforms/index.html for more info.

If unsupported, FreeBSD must be upgraded by source.
=====================
why?

 

[richardtoohey2]

Yes.

Maybe this will help? https://forums.freebsd.org/threads/i-would-have-thought.82241/

 

[ralphbsz]

That platform (amd64) and that release (13.0) are definitely supported by automatic upgrades.

The problem is that the above error message, while correct in a theoretical sense, is also very unhelpful. What it really says: "While attempting to upgrade, something went wrong. It might be a networking problem, it might be a misconfiguration of your machine, or it might be that the combination of your platform and release really are unsupported. We can't be bothered to distinguish between these errors, so we give a generic messages, which in most cases is misleading but theoretically not wrong."

Please diagnose what is wrong with your network connectivity, and fix it. Once that is done, the problem will likely go away.

 

[Phishfry]

freebsd-update still works on my i386 'Tier 2' platforms.
I updated 13.1RC to 13.1-RELEASE via it just the other day.