error connecting to n8n could not connect to server. refresh to try again

Not specified by the original author.

TL;DR

For "TypeError: can't access property "ldap", options.config is undefined": i updated my self-hosted n8n to 1.109.1 and now the web UI shows a red banner: "Error connecting to n8n Could not connect to server.

TypeError: can't access property "ldap", options.config is undefined

Steps

1. I updated my self-hosted n8n to 1.109.1 and now the web UI shows a red banner: "Error connecting to n8n Could not connect to server. Refresh to try again." The backend container looks healthy. Downgrading to 1.108 makes it work again. I run n8n in Docker behind a plain setup, no SSO. What broke?
2. This was a real regression in the 1.109-1.121 range, not your config. From n8n 1.120 on, the new SSO initialization runs even when you do not use SSO, and if the SSO config vars do not exist in your setup the frontend crashes during init with TypeError: can't access property "ldap", options.config is undefined, which surfaces as the red "Error connecting to n8n" banner. Two verified fixes: update to 1.121.2 or the next docker tag (users confirmed the pre-release resolves it with no config changes), or if you want to stay on your version, explicitly disable the SSO features you are not using by adding these to your environment: N8NSSOSAMLENABLED=false, N8NSSOOIDCENABLED=false, N8NSSOLDAP_ENABLED=false, then restart the container. You can confirm the diagnosis before touching anything by opening the browser console (F12) and looking for the ldap TypeError.

When to use

You are seeing this: Refresh to try again." The backend container looks healthy. Use this skill when you run into ""Error connecting to n8n Could not connect to server" after upgrading to 1.109.1".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

Versions mentioned in the source: 1.109.1, 1.109-1.121, 1.121.2. If you are on something much newer or older, the details may have shifted.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Sources

• https://github.com/n8n-io/n8n/issues/19151

Someone asked: I updated my self-hosted n8n to 1.109.1 and now the web UI shows a red banner: "Error connecting to n8n Could not connect to server. Refresh to try again." The backend container looks healthy. Downgrading to 1.108 makes it work again. I run n8n in Docker behind a plain setup, no SSO. What broke? The verified resolution: This was a real regression in the 1.109-1.121 range, not your config. From n8n 1.120 on, the new SSO initialization runs even when you do not use SSO, and if the SSO config vars do not exist in your setup the frontend crashes during init with TypeError: can't access property "ldap", options.config is undefined, which surfaces as the red "Error connecting to n8n" banner. Two verified fixes: update to 1.121.2 or the next docker tag (users confirmed the pre-release resolves it with no config changes), or if you want to stay on your version, explicitly disable the SSO features you are not using by adding these to your environment: N8NSSOSAMLENABLED=false, N8NSSOOIDCENABLED=false, N8NSSOLDAPENABLED=false, then restart the container. You can confirm the diagnosis before touching anything by opening the browser console (F12) and looking for the ldap TypeError. Thread: https://vectle.com/threads/thrpVmmsS24cDngVkQEFDxcJg

Not specified by the original author.

TL;DR

Fix: Reporter-confirmed fix (antman1p): add an explicit nginx location block for /rest/push with proxyhttpversion 1.1, Upgrade/Connection headers and Origin/X-Forwarded headers, e.g. location /rest/push { proxypass http://n8n:5678; proxysetheader Upgrade $httpupgrade; proxysetheader Connection 'upgrade'; proxysetheader Origin ...; }. Member Joffcom closed the issue after the nginx-config guidance resolved it.

The error

Issue n8n-io/n8n#14653 (closed, 80 comments): ### Bug Description After the upgrade I started to get error index-D76xStxp.js:293035 [WebSocketClient] Connection lost, code=1008 onConnectionLost @ index-D76xStxp.js:29303 ### To Reproduce 1. Use nginx with reverse proxy 2. Upgrade to 1.88.0 3. WS failing to connect ### Expected behavior WS works as intended ### Operating System Ubuntu 22.04.5 LTS ### n8n Version 1.88.0 ### Node.js Version 21.7.3 ### Database PostgreSQL ### Execution mode main (default)

Fix

1. Reporter-confirmed fix (antman1p): add an explicit nginx location block for /rest/push with proxyhttpversion 1.1, Upgrade/Connection headers and Origin/X-Forwarded headers, e.g. location /rest/push { proxypass http://n8n:5678; proxysetheader Upgrade $httpupgrade; proxysetheader Connection 'upgrade'; proxysetheader Origin ...; }.
2. Member Joffcom closed the issue after the nginx-config guidance resolved it.

Success check: the symptom above is gone and the original operation completes.

When to use

• You hit this exact symptom in n8n.
• You want the verified fix without digging through the thread.

When not to use

• A different error in n8n, even a similar-looking one.
• General n8n setup or credential questions.

Compatibility

• N8n (n8n-io/n8n) Reported against version 1.88.0.

Variant phrasings

• How to fix "connection lost after upgrade to 1.88.0" in n8n
• n8n: connection lost after upgrade to 1.88.0

Edge cases

• After upgrading to 1.88.0, the editor websocket (/rest/push) failed with code 1008 behind nginx reverse proxies.

Source

• https://github.com/n8n-io/n8n/issues/14653

In gh:n8n-io/n8n#14653 (https://github.com/n8n-io/n8n/issues/14653), someone reported: Issue n8n-io/n8n#14653 (closed, 80 comments): ### Bug Description After the upgrade I started to get error index-D76xStxp.js:293035 [WebSocketClient] Connection lost, code=1008 onConnectionLost @ index-D76xStxp.js:29303 ### To Reproduce 1. Use nginx with reverse proxy 2. Upgrade to 1.88.0 3. WS failing to connect ### Expected behavior WS works as intended ### Operating System Ubuntu 22.04.5 LTS ### n8n Version 1.88.0 ### Node.js Version 21.7.3 ### Database PostgreSQL ### Execution mode main (default) The verified resolution from the thread: After upgrading to 1.88.0, the editor websocket (/rest/push) failed with code 1008 behind nginx reverse proxies. Reporter-confirmed fix (antman1p): add an explicit nginx location block for /rest/push with proxyhttpversion 1.1, Upgrade/Connection headers and Origin/X-Forwarded headers, e.g. location /rest/push { proxypass http://n8n:5678; proxysetheader Upgrade $httpupgrade; proxysetheader Connection 'upgrade'; proxysetheader Origin ...; }. Member Joffcom closed the issue after the nginx-config guidance resolved it.

Not specified by the original author.

TL;DR

Install the Weaviate node in n8n instead of building a custom wrapper. The Weaviate node for n8n was published; the maintainer closed the issue announcing it with a link to the Weaviate blog post on the n8n integration.

Steps

1. The Weaviate node for n8n was published; the maintainer closed the issue announcing it with a link to the Weaviate blog post on the n8n integration. Install the Weaviate node in n8n instead of building a custom wrapper. One caveat from the thread: a later commenter could not find it as a community node and thought it might only be in n8n Cloud, so check availability for your n8n edition before relying on it.

When to use

You are seeing this: It would be nice if you could publish and maintain a n8n wrapper node to interact with weaviate. n8n if among the most used LLM no-code / low-code LLM app tools, and it's missing an integration with one of the best VectorDB :( Use this skill when you run into "Weaviate n8n wrapper".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Edge cases

• One caveat from the thread: a later commenter could not find it as a community node and thought it might only be in n8n Cloud, so check availability for your n8n edition before relying on it.

In gh:weaviate/weaviate#7302 (https://github.com/weaviate/weaviate/issues/7302), the reporter ran into this: It would be nice if you could publish and maintain a n8n wrapper node to interact with weaviate. n8n if among the most used LLM no-code / low-code LLM app tools, and it's missing an integration with one of the best VectorDB :( The verified resolution: The Weaviate node for n8n was published; the maintainer closed the issue announcing it with a link to the Weaviate blog post on the n8n integration. Install the Weaviate node in n8n instead of building a custom wrapper. One caveat from the thread: a later commenter could not find it as a community node and thought it might only be in n8n Cloud, so check availability for your n8n edition before relying on it.