[Bug]: Cannot pick a name because of 'invalid_name' despite it being green in the name box and not being taken.

[pleasehugme]

Requirements

• [X] Is this a bug report? For questions or discussions use https://lemmy.ml/c/lemmy_support
• [X] Did you check to see if this issue already exists?
• [X] Is this only a single bug? Do not put multiple bugs in one issue.
• [X] Is this a backend issue? Use the lemmy-ui repo for UI / frontend issues.

Summary

I cannot have the username of my choice for some reason, and thus cannot register.

Steps to Reproduce

1. Input all other details except your name
2. Input the username PostApocalypticHeroics
3. Look at the website in frustration as you keep trying and trying, always rejected for some reason

Technical Details

OS: Windows 10, Opera GX. No browser console errors AFAIK. Only error is literally:

invalid_name

Version

BE 0.18.2

Lemmy Instance URL

ttrpg.network

[WayneSheppard]

Username too long? Looks like the DB limits it to 20 characters.

create table user_ ( id serial primary key, name varchar(20) not null, fedi_name varchar(40) not null, preferred_username varchar(20),