Debug ID: D20347597 | The Zotero Connector was unable to communicate with the Zotero desktop app...

kmilgram · 2026-01-30T01:33:36+00:00

I have a problem with Zotero 8.0.1 x64 on Linux Mint: the "Zotero Connector" is running on the wrong port and won't connect to the Zotero client.

https://s3.amazonaws.com/zotero.org/images/forums/u3116/e13h0xljcrmu0da3pngu.png

The problem started after the upgrade-in-place procedure completed.

## OS Info

```
eric@envy:~$ cat /etc//os-release
NAME="Linux Mint"
VERSION="21.3 (Virginia)"
ID=linuxmint
ID_LIKE="ubuntu debian"
PRETTY_NAME="Linux Mint 21.3"
VERSION_ID="21.3"
HOME_URL="https://www.linuxmint.com/"
SUPPORT_URL="https://forums.linuxmint.com/"
BUG_REPORT_URL="http://linuxmint-troubleshooting-guide.readthedocs.io/en/latest/"
PRIVACY_POLICY_URL="https://www.linuxmint.com/"
VERSION_CODENAME=virginia
UBUNTU_CODENAME=jammy
eric@envy:~$
```

```
eric@envy:~$ zotero --version
Zotero Zotero 140.7.0esr, Copyright (c) 2006-2025 Contributors
eric@envy:~$
```

In the browser, http://127.0.0.1:23124/connector/ping returns "Zotero is running".

```html
eric@envy:~$ html-beautify < <(curl -is --max-time 3 http://127.0.0.1:23124/connector/ping | tail -n 1)
<!DOCTYPE html>

Zotero is running

eric@envy:~$
eric@envy:~$
```

---

http://127.0.0.1:23119/connector/ping returns nothing in the browser.

```
eric@envy:~$ curl -i --max-time 3 http://127.0.0.1:23119/connector/ping
curl: (7) Failed to connect to 127.0.0.1 port 23119 after 0 ms: Connection refused
eric@envy:~$
```

---

`zotero-bin` is binding to 3 ports: 19876, 23116, and 23124.

| Netid | State | Recv-Q | Send-Q | Local Address:Port | Peer Address:Port | Process |
| ----- | ------ | ------ | ------ | ------------------ | ----------------- | --------------------------------------- |
| tcp | LISTEN | 0 | 5 | 127.0.0.1:19876 | 0.0.0.0:* | users:(("zotero-bin",pid=107161,fd=98)) |
| tcp | LISTEN | 0 | 5 | 127.0.0.1:23116 | 0.0.0.0:* | users:(("zotero-bin",pid=107161,fd=97)) |
| tcp | LISTEN | 0 | 37 | 127.0.0.1:23124 | 0.0.0.0:* | users:(("zotero-bin",pid=107161,fd=96)) |

When the Zotero app is closed, nothing is returned.

---

1. Can the connector port be changed?

2. Do you know why the server might be starting on port 23124 instead of port 23119?

kmilgram · 2026-01-30T01:37:08+00:00

Just in case it's helpful.

```
eric@envy:~$ curl -is --max-time 3 http://127.0.0.1:23124/connector/ping
HTTP/1.0 200 OK
X-Zotero-Version: 8.0.1
X-Zotero-Connector-API-Version: 3
Content-Type: text/html

<!DOCTYPE html>Zotero is runningeric@envy:~$

```

https://s3.amazonaws.com/zotero.org/images/forums/u3116/vc8e5bbqlylut51ypkc6.png

kmilgram · 2026-01-30T01:52:24+00:00

You can close this. I found this helpful documentation here on the Zotero site that explains how to change the port address of either the connector or the http server:

https://www.zotero.org/support/preferences/hidden_preferences

I accessed the settings in the Zotero client and changed the port from 23123 to 23119, saved the settings, closed the app, and restarted it. Then, the connector worked fine.

Do you have any idea why this port setting might have gotten changed?