From time to time I have to assign complex passwords and give hard copies to users. Notepad font routinely confuses them. They mistake a lowercase l for a 1, etc. Which font is clearest?
Look into fonts optimized for source code, like <a href="https://www.google.com/fonts/specimen/Source+Code+Pro" rel="nofollow">https://www.google.com/fonts/specimen/Source+Code+Pro</a><p>If you have control over how the passwords look, you maybe also could adjust their generation to avoid hard-to-distinguish sequences.