IDE hangs on startup: "Error: 14 UNAVAILABLE: No connection established"

I downloaded the Arduino IDE version 2.3.6 on my new computer, but it got stuck at the startup screen after running.
I have already tried the method of uninstalling and reinstalling, and I have also browsed the relevant topics on the forum, but none of them could solve my problem.
The operating system I am using is Windows 10.
Here is the running log that I have extracted:

2025-07-14 16:49:37 Arduino IDE 2.3.6
2025-07-14 16:49:37 Checking for frontend application configuration customizations. Module path: C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\electron-main.js, destination 'package.json': C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\package.json
2025-07-14 16:49:37 Setting 'theia.frontend.config.appVersion' application configuration value to: "2.3.6" (type of string)
2025-07-14 16:49:37 Setting 'theia.frontend.config.cliVersion' application configuration value to: "1.2.0" (type of string)
2025-07-14 16:49:37 Setting 'theia.frontend.config.buildDate' application configuration value to: "2025-04-09T11:26:55.498Z" (type of string)
2025-07-14 16:49:37 Frontend application configuration after modifications: {"applicationName":"Arduino IDE","defaultTheme":{"light":"arduino-theme","dark":"arduino-theme-dark"},"defaultIconTheme":"none","electron":{"windowOptions":{},"showWindowEarly":true,"splashScreenOptions":{},"uriScheme":"arduino-ide"},"defaultLocale":"","validatePreferencesSchema":false,"reloadOnReconnect":true,"uriScheme":"theia","preferences":{"window.title":"${rootName}${activeEditorShort}${appName}","files.autoSave":"afterDelay","editor.minimap.enabled":false,"editor.tabSize":2,"editor.scrollBeyondLastLine":false,"editor.quickSuggestions":{"other":false,"comments":false,"strings":false},"editor.maxTokenizationLineLength":500,"editor.bracketPairColorization.enabled":false,"breadcrumbs.enabled":false,"workbench.tree.renderIndentGuides":"none","explorer.compactFolders":false},"appVersion":"2.3.6","cliVersion":"1.2.0","buildDate":"2025-04-09T11:26:55.498Z"}
2025-07-14 16:49:37 Starting backend process. PID: 12032
2025-07-14 16:49:37 Showing main window early
2025-07-14 16:49:37 Using browser-only version of superagent in non-browser environment
2025-07-14 16:49:37 Configuration directory URI: 'file:///c%3A/Users/qian_work/.arduinoIDE'
2025-07-14 16:49:37 Configuring to accept webviews on '^.+\.webview\..+$' hostname.
2025-07-14 16:49:37 2025-07-14T08:49:37.693Z root INFO Backend u.initialize: 25.7 ms [Finished 0.553 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.697Z root INFO Backend Object.initialize: 23.3 ms [Finished 0.553 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.697Z root INFO Backend a.initialize: 1.3 ms [Finished 0.553 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.697Z root INFO Backend a.initialize: 1.1 ms [Finished 0.553 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.697Z root INFO Backend u.initialize: 1.4 ms [Finished 0.553 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.699Z root INFO Backend l.initialize: 24.5 ms [Finished 0.554 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.705Z root INFO configured all backend app contributions
2025-07-14 16:49:37 2025-07-14T08:49:37.706Z root INFO Backend l.onStart: 1.1 ms [Finished 0.566 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.706Z root INFO Backend d.onStart: 0.1 ms [Finished 0.567 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z root INFO Backend a.onStart: 0.3 ms [Finished 0.567 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z config INFO >>> Initializing CLI configuration...
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z root INFO Backend x.onStart: 0.3 ms [Finished 0.567 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z config INFO Loading CLI configuration from c:\Users\qian_work\.arduinoIDE\arduino-cli.yaml...
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z daemon INFO Starting daemon from C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\resources\arduino-cli.exe...
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z root INFO Backend w.onStart: 0.3 ms [Finished 0.568 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z discovery-log INFO start
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z discovery-log INFO start new deferred
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z root INFO Backend v.onStart: 0.2 ms [Finished 0.568 s after backend start]
2025-07-14 16:49:37 2025-07-14T08:49:37.707Z root INFO Backend a.onStart: 0.1 ms [Finished 0.568 s after backend start]
2025-07-14 16:49:38 2025-07-14T08:49:38.274Z root INFO Theia app listening on http://127.0.0.1:49476.
2025-07-14 16:49:38 2025-07-14T08:49:38.274Z root INFO Finished starting backend application: 566.5 ms [Finished 1.135 s after backend start]
2025-07-14 16:49:38 2025-07-14T08:49:38.275Z root WARN The local plugin referenced by local-dir:/c%3A/Users/qian_work/.arduinoIDE/plugins does not exist.
2025-07-14 16:49:38 2025-07-14T08:49:38.275Z root WARN The local plugin referenced by local-dir:/c%3A/Users/qian_work/.arduinoIDE/deployedPlugins does not exist.
2025-07-14 16:49:38 2025-07-14T08:49:38.275Z root WARN The local plugin referenced by local-dir:C:\Users\qian_work\.arduinoIDE\plugins does not exist.
2025-07-14 16:49:38 2025-07-14T08:49:38.304Z config INFO Loaded CLI configuration: {"board_manager":{"additional_urls":[]}}
2025-07-14 16:49:38 2025-07-14T08:49:38.304Z config INFO Loading fallback CLI configuration to get 'directories.data' and 'directories.user'
2025-07-14 16:49:38 2025-07-14T08:49:38.338Z root INFO Resolve plugins list: 629.5 ms [Finished 1.199 s after backend start]
2025-07-14 16:49:38 2025-07-14T08:49:38.385Z daemon INFO time="2025-07-14T16:49:38+08:00" level=info msg="arduino-cli version 1.2.0"
2025-07-14 16:49:38 2025-07-14T08:49:38.388Z daemon INFO time="2025-07-14T16:49:38+08:00" level=info msg="Using config file: c:\\Users\\qian_work\\.arduinoIDE\\arduino-cli.yaml"
2025-07-14 16:49:38 2025-07-14T08:49:38.388Z daemon INFO time="2025-07-14T16:49:38+08:00" level=info msg="Executing `arduino-cli daemon`"
2025-07-14 16:49:38 2025-07-14T08:49:38.401Z daemon INFO Daemon is now listening on 127.0.0.1:49478
{"IP":"127.0.0.1","Port":"49478"}
2025-07-14 16:49:38 2025-07-14T08:49:38.401Z daemon INFO Daemon is running.
2025-07-14 16:49:38 2025-07-14T08:49:38.410Z config INFO Loaded fallback CLI configuration: {"directories":{"user":"C:\\Users\\qian_work\\Documents\\Arduino","data":"C:\\Users\\qian_work\\AppData\\Local\\Arduino15"}}
2025-07-14 16:49:38 2025-07-14T08:49:38.410Z config INFO Merged CLI configuration with the fallback: {"directories":{"user":"C:\\Users\\qian_work\\Documents\\Arduino","data":"C:\\Users\\qian_work\\AppData\\Local\\Arduino15"},"board_manager":{"additional_urls":[]}}
2025-07-14 16:49:38 2025-07-14T08:49:38.410Z config INFO Loaded the CLI configuration.
2025-07-14 16:49:38 2025-07-14T08:49:38.420Z config INFO Mapped the CLI configuration: {"dataDirUri":"file:///c%3A/Users/qian_work/AppData/Local/Arduino15","sketchDirUri":"file:///c%3A/Users/qian_work/Documents/Arduino","additionalUrls":[],"network":"none","locale":"en"}
2025-07-14 16:49:38 2025-07-14T08:49:38.420Z config INFO Validating the CLI configuration...
2025-07-14 16:49:38 2025-07-14T08:49:38.420Z config INFO The CLI config is valid.
2025-07-14 16:49:38 2025-07-14T08:49:38.420Z config INFO <<< Initialized the CLI configuration.
2025-07-14 16:49:38 2025-07-14T08:49:38.727Z root ERROR Uncaught Exception:  Error: 14 UNAVAILABLE: No connection established. Last error: Error: connect ETIMEDOUT 127.0.0.1:49478
2025-07-14 16:49:38 2025-07-14T08:49:38.727Z root ERROR Error: 14 UNAVAILABLE: No connection established. Last error: Error: connect ETIMEDOUT 127.0.0.1:49478
    at t.callErrorFromStatus (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:3089094)
    at Object.onReceiveStatus (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:6679669)
    at Object.onReceiveStatus (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:2572294)
    at Object.onReceiveStatus (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:2571739)
    at C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:4307911
    at process.processTicksAndRejections (node:internal/process/task_queues:77:11)
for call at
    at s.makeUnaryRequest (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:6679200)
    at s.create (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:3088187)
    at instance (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:6283083)
    at new Promise (<anonymous>)
    at y.createClient (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:6283060)
    at y.create (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:6281968)
    at C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:6280864
    at C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:1018551
    at s.invoke (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:1018641)
    at a.fire (C:\Users\qian_work\AppData\Local\Programs\arduino-ide\resources\app\lib\backend\main.js:2:1020444)
2025-07-14 16:49:38 2025-07-14T08:49:38.860Z root INFO Deploy plugins list: 1151.9 ms [Finished 1.721 s after backend start]
2025-07-14 16:51:00 Stored workspaces roots: 
2025-07-14 16:51:00 No sketches were scheduled for deletion.

Welcome to the forum

On first startup after installation IDE2.x connects to the Internet to download some of the files needed to set it up

Has your PC got Internet access ?

Of course there is an internet connection.

Why "Of course" ?

My computer is connected to the internet, and the Arduino software also has network access permissions.