unbound-daemon: unable to use DoT error: SSL_write syscall: Connection reset by peer

[easyteacher]

Maintainer: @EricLuehrsen @BKPepe @hardfalcon
Environment: (put here arch, model, OpenWrt version)
Model | GL.iNet GL-MT1300
Architecture | MediaTek MT7621 ver:1 eco:3
Firmware Version | OpenWrt SNAPSHOT r21222+1-ceb1451c10 / LuCI Master git-22.312.55390-37468c9
Kernel Version | 5.15.77

Description:
unbound is not able to use DNS over TLS. Any request will generate the log error: SSL_write syscall: Connection reset by peer. This seems to be an arch-related problem. DoT was working in unbound 1.13.x

Config: unbound.txt

See also: https://forum.openwrt.org/t/unbound-dns-over-tls-problem-on-master/109569

[EricLuehrsen]

I do not have experience digging into this hardware. Did some SSL option enable any hardware intrinsic maybe?