The custom TWRP 3.2.3 version this topic here is about can decrypt 14.1 encryption just fine … there are still problems with 15.1 and 16.0 encryption (not the same problems official TWRP 3.3.0-0 has, but problems).
Regarding LineageOS 16.0 … it currently will not work on 14.1 encryption anyway.
Just flash (or install via TWRP) the TWRP 3.2.3-0 image again, same way as you did with 3.3.0-0.