Anker Keyboard Not Working on iPad
I saw a 2017 post that talks about this very issue that I'm having right now. Some of the keys don't work, like the LETTERS. Other keys work, like ON and LOCK and all of the keys at the top, namely, Esc, brightness up, brightness down, search, iPad keyboard, back, pause/play, forward, Mute, volume up, volume down. The answer that was marked as helpful in the 2017 post was to change Keyboard settings from Automatic to U. S. Since my keyboard setting was already set to U.S., I changed to Automatic.
Adjusting the keyboard setting works either way. It's unfortunate that this glitch persists today in June 2020, while Apple has known about it since 2017. It appears that that's how they roll, unfortunately.