I have the same problem:
Connection failed. If the problem persists, please check your internet connection or VPN
Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools [internal]
(Request ID: a64846b5-83e2-4a6a-b980-85d7a992c67c)
Nothing help…
hi @Zhenua_Klimenko @kocean33 which Cursor version are you using? Could you update to 1.4.2 if you have not yet?
Version: 1.4.2 (Universal)
VSCode Version: 1.99.3
Request ID: 2e40a049-aa93-4346-ae52-2e0fad32dac5
ConnectError: [internal] Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools
at vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:4918:250162
Fix: It worked after creating an another instance of chat. I also linked the past chat as context to continue where I stopped.
I’m using 1.4.2 on macOS
I fixed by disable “auto-fix Lints” feature
NO It didn’t fixed
when i debug the agent function
function Dko(i, e, t, n) {
kL(e !== void 0);
const s = i.repeated;
switch (i.kind) {
case "scalar":
case "enum":
let r = i.kind == "enum" ? Sl.INT32 : i.T;
if (s)
if (kL(Array.isArray(e)),
i.packed)
cqc(t, r, i.no, e);
else
for (const o of e)
Y1t(t, r, i.no, o);
else
Y1t(t, r, i.no, e);
break;
case "message":
if (s) {
kL(Array.isArray(e));
for (const o of e)
Rko(t, n, i, o)
} else
Rko(t, n, i, e);
break;
case "map":
kL(typeof e == "object" && e != null);
for (const [o,a] of Object.entries(e))
lqc(t, n, i, o, a);
break
}
}
e: 2147483648
i : {
"no": 2,
"name": "column",
"kind": "scalar",
"T": 5,
"localName": "column",
"jsonName": "column",
"repeated": false,
"L": 0,
"delimited": false,
"req": false,
"opt": false,
"packed": true
}
s: <value unavailavle>
t: {
"stack": [],
"textEncoder": {},
"chunks": [],
"buf": [
8,
160,
1,
16
]
}
and then they bring this data to fuction rqc().writeMessage
writeMessage(i, e, t) {
const n = i.getType();
for (const s of n.fields.byNumber()) {
if (!wko(s, i)) {
if (s.req)
throw new Error(`cannot encode field ${n.typeName}.${s.name} to binary: required field not set`);
continue
}
const r = s.oneof ? i[s.oneof.localName].value : i[s.localName];
Dko(s, r, e, t)
}
return t.writeUnknownFields && this.writeUnknownFields(i, e),
e
},
Dko(s:{
"no": 2,
"name": "range",
"kind": "message",
"localName": "range",
"jsonName": "range",
"repeated": false,
"delimited": false,
"req": false,
"opt": false,
"packed": false
}
r: {
"startPosition": {
"line": 160,
"column": 1
},
"endPosition": {
"line": 160,
"column": 2147483648
}
}
e: {
"stack": [],
"textEncoder": {},
"chunks": [
{
"0": 10,
"1": 28
},
{
"0": 84,
"1": 111,
"2": 111,
"3": 32,
"4": 109,
"5": 97,
"6": 110,
"7": 121,
"8": 32,
"9": 98,
"10": 108,
"11": 97,
"12": 110,
"13": 107,
"14": 32,
"15": 108,
"16": 105,
"17": 110,
"18": 101,
"19": 115,
"20": 32,
"21": 40,
"22": 50,
"23": 32,
"24": 62,
"25": 32,
"26": 48,
"27": 41
}
],
"buf": [
18
]
}
t: {
"writeUnknownFields": true
})
--------
i: {
"message": "Too many blank lines (2 > 0)",
"range": {
"startPosition": {
"line": 160,
"column": 1
},
"endPosition": {
"line": 160,
"column": 2147483648
}
},
"relatedInformation": [],
"severity": "DIAGNOSTIC_SEVERITY_ERROR"
}
e: {
"stack": [],
"textEncoder": {},
"chunks": [
{
"0": 10,
"1": 28
},
{
"0": 84,
"1": 111,
"2": 111,
"3": 32,
"4": 109,
"5": 97,
"6": 110,
"7": 121,
"8": 32,
"9": 98,
"10": 108,
"11": 97,
"12": 110,
"13": 107,
"14": 32,
"15": 108,
"16": 105,
"17": 110,
"18": 101,
"19": 115,
"20": 32,
"21": 40,
"22": 50,
"23": 32,
"24": 62,
"25": 32,
"26": 48,
"27": 41
}
],
"buf": [
18
]
}
Too many blank lines (2 > 0)
this message is from “ansbile-lint”. i hope this help you debug this bug
same error, currently on
Version: 1.4.2
VSCode Version: 1.99.3
Commit: d01860bc5f5a36b62f8a77cd42578126270db340
Date: 2025-08-07T17:16:23.005Z (13 hrs ago)
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin arm64 23.6.0
Connection failed. If the problem persists, please check your internet connection or VPN
Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools [internal]
Also experiencing the same error on:
Version: 1.4.2
VSCode Version: 1.99.3
Commit: 07aa3b4519da4feab4761c58da3eeedd253a1670
Date: 2025-08-06T19:23:39.081Z (1 day ago)
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.6.0
Means you have to abandon the chat and start a new one. There is no way of continuing as it results in the same error over and over.
I’d say this happens in about 1 out 4 chats which is incredibly frustrating having to start over each time
I’m also experiencing the same error.
After tasked with completing todos
Request ID: 25c871eb-ce8f-40d5-833d-1efff40a823a
ConnectError: [internal] Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools
at vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:4846:222865
Since the last update, I keep getting this.
Connection failed. If the problem persists, please check your internet connection or VPN
Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools [internal]
(Request ID: 2b75238a-fa4f-4a50-82e9-b80d96928382)
Connection failed. If the problem persists, please check your internet connection or VPN
Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools [internal]
(Request ID: dd9a950a-188c-411f-8549-7ab3e51eefcf)
I am also receiving this error. The workaround is to create a brand new chat, and lose the last chat history and context.
Connection failed. If the problem persists, please check your internet connection or VPN
Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools [internal]
(Request ID: a6de7fc7-f748-4418-9d7a-5bbccb2a216a)
@sicamarketing @Vibe @Ruben-Tjok @Suzi_S which Cursor version do you use?
I would like to update the internal ticket.
Open the Cursor settings → switch to the Chat tab → disable “Auto-Fix Lints” to temporarily avoid this error, but need to fix some lint issues manually.
Same issue here—I got this error when Cursor was fixing the lint issues:
Request ID: 15f62c26-0d5f-4fe7-9b94-8ef7d2876f91
ConnectError: [internal] Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools
at vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:4918:250162
Here is the Cursor information:
Version: 1.4.3 (Universal)
VSCode Version: 1.99.3
Commit: e50823e9ded15fddfd743c7122b4724130c25df0
Date: 2025-08-08T17:34:53.060Z
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.5.0
I’m also seeing this error:
Request ID: 68459347-26ab-4ea3-8c78-738305c7b5a1
ConnectError: [internal] Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools
at vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:4918:250162
with
Version: 1.4.5 (Universal)
VSCode Version: 1.99.3
Commit: af58d92614edb1f72bdd756615d131bf8dfa5290
Date: 2025-08-13T02:08:56.371Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.6.0
Same. It’s happening across many versions, new chat or old, no matter which model.
Connection failed. If the problem persists, please check your internet connection or VPN
Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools [internal]
(Request ID: ba6fb099-29c3-45b8-b0b3-a4be97c0e984)
The worst part is, it charges you for the tokens it used before suddenly getting this error.
I’m seeing this error:
Connection failed. If the problem persists, please check your internet connection or VPN
Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools [internal]
Version: 1.4.5 (user setup)
VSCode Version: 1.99.3
Commit: af58d92614edb1f72bdd756615d131bf8dfa5290
Date: 2025-08-13T02:08:56.371Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Windows_NT x64 10.0.26100
Started failing now for me, using Claude 4 Sonnet.
The error reads:
“Connection failed. If the problem persists, please check your internet connection or VPN
Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools [internal]”
Cursor IDE
Request Information:
Request ID: 5e5833ba-eba3-4379-814f-214ede4630f8
ConnectError: [internal] Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools
at vscode-file://vscode-app/c:/Users/Buffe/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:4918:250162
I prompted Cursor to do the following:
Please proceed with implementing the proposed enhancements:
Add logging for all incoming request data (headers, GET, POST, raw body).
Add more granular try/catch blocks around risky operations (e.g., file operations, runner execution).
Ensure output buffer is always closed, even on error.
Log the final response sent to the client.
(Optional) Add a shutdown function to catch fatal errors.
Ideally, it would perform the requested actions.
Windows 10/11
Version: 1.4.5 (user setup)
VSCode Version: 1.99.3
Commit: af58d92614edb1f72bdd756615d131bf8dfa5290
Date: 2025-08-13T02:08:56.371Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Windows_NT x64 10.0.19045
Sometimes - I can sometimes use Cursor
Cursor IDE
After every requests it stops and I get this error.
Connection failed. If the problem persists, please check your internet connection or VPN
Serialization error in aiserver.v1.StreamUnifiedChatRequestWithTools [internal]
(Request ID: 682c64f1-a953-482d-9d8c-cd09b2d00905)
Just open the AI plane
MacOS
Version: 1.4.5
VSCode Version: 1.99.3
Commit: af58d92614edb1f72bdd756615d131bf8dfa5290
Date: 2025-08-13T02:08:56.371Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.1.0
Yes - Cursor is unusable
hi everyone and thank you for your posts. Our engineers are looking into this.