unable to enter SSH public key for user access with ConnectPort TS 16

In the User Access section under User Configuration, I am attempting to enter an SSH public key. No matter what I try (RSA or DSA, 1024 or 2048 bits, from puttygen or ssh-keygen), I get the “Invalid or missing SSH Public Key” error after pasting the key and pressing Apply. I haven’t found anything online that specifically addresses the ConnectPort devices, but I’ve followed the directions for similar Digi devices (in particular, pasting the entire key text). Suggestions?

Digi confirms a bug in the web interface with firmware version J2 (still the current version as of 2017.09.08). Should be okay with J or J1. Digi says you can also use the command line with J2 (set user id=3 public_key= using a TFTP server.