Can’t Join the Server? Fixing “Unknown Account Username Given” in Project Zomboid

Same credentials still rejected

1. Confirm you are connecting to the same server entry (IP/port or favorites row), not a different world with a similar name.
2. Re-enter the account password carefully. A wrong password usually shows a different message, but a wiped or recreated account can still look like “unknown username.”
3. Ask an admin whether the world/user database was reset, whether Open changed to false, or whether your account was removed with /removeuserfromwhitelist.
4. If the account is gone, the admin should recreate it with /adduser "YourName" "password" and tell you the exact credentials to use.

Password fields and username spelling

1. Use the account username/password fields for the server’s per-player account. If the server also has a separate server password, put that only in the server-password field.
2. Username lookup is case-insensitive: SurvivorBob and survivorbob resolve to the same account. Spelling and extra spaces still matter.
3. If the server disallows non-ASCII names, the client can show a different message: Username contains non-Ascii characters. That is not the same as “unknown account.”
4. If you truly forgot the password and the admin cannot reset it safely, they must remove and re-add the account with the built-in commands—not by guessing database rows.

Invite-only or wiped server

1. Contact the host. On Open=false, an admin must create username/password combos before new logins work.
2. Ask them to run /adduser "YourName" "password", then join with those exact credentials.
3. Optional host-side helpers: /addusertowhitelist "username" for an already-connected passworded user, and /removeuserfromwhitelist "username" to revoke access.
4. Steam invites help you find the host session, but they do not replace whitelist account creation when Open=false.

Private / whitelisted server

You need a pre-created account. Ask the admin for a username and password, then use those on the Join screen.

Admin command: /adduser "username" "password" — the password argument can be omitted in the command form, but players still need whatever credentials the host chose.

Public server still rejects you

1. Try a second public server. If only one fails, that host’s Open setting or user database is the problem.
2. Avoid leading/trailing spaces when pasting a username.
3. If your name uses non-Latin characters and you see the non-ASCII failure text, try an ASCII username or ask the host to enable AllowNonAsciiUsername.
4. Do not treat a fixed “under 20 characters” limit as an official universal rule. Use a clear username the host can type back exactly.

When the server type is unclear

1. Read the server description and Discord/community notes for “whitelist,” “apply,” or “register first.”
2. Try one clean ASCII username with a password you will remember. If it fails immediately with this error, treat the server as closed/whitelisted.
3. Ask the host: is Open true or false? Do I need an /adduser account first?
4. If you only wanted a casual public game, pick another server marked open in the browser.

Host: open the server for new accounts

1. In Server Settings (or the server .ini for your server name), set Open=true.
2. With Open on, clients may join without already having a whitelist account.
3. Optional: set AutoCreateUserInWhiteList=true so unknown usernames are written into the whitelist when players join (intended for Open=true servers).
4. Save, fully restart the server, then have a player join with a new username and password.

Open=true
AutoCreateUserInWhiteList=true

Host: private whitelist workflow

1. Set Open=false. Administrators must manually create username/password combos.
2. Restart the server.
3. For each player, run: /adduser "FriendName" "password".
4. Send players those credentials. They should use the account fields on Join—not invent a new name unless you create it first.
5. To revoke access later: /removeuserfromwhitelist "username".

Do not hand-edit the user database as a first step. Prefer the built-in commands and your host panel’s whitelist tools.