How to fix logging in timeout error while sideloading Excel add-in for M365 using Yeoman generator.

Question

How to fix logging in timeout error while sideloading Excel add-in for M365 using Yeoman generator.

Ronald Taff 0

when trying to sideload my excel add-in using Yeoman generator I get a time out error logging in to m365.

[Login] Failed to retrieve token silently.

0 comments

2 answers

Your answer

Answer 1

For Yeoman-generated Office Add-ins, a login timeout during sideloading is addressed by signing in to Microsoft 365 from the command line first.

Open a command prompt or terminal in the project root.
Run:
```
   atk auth login m365
```
Complete the Microsoft 365 sign-in flow in the browser window that opens.
After sign-in succeeds, run the sideload command again:
```
   npm start
```

Additional checks supported by the setup guidance:

Use HTTPS, not HTTP, for the local dev server. If prompted, install the development certificate provided by the Yeoman generator. Administrative privileges may be required.
If prompted with "Allow localhost loopback for Microsoft Edge WebView?", enter Y. This requires administrator privileges and is needed on first-time Office Add-in development setups.
On Mac, start the local web server first with:
```
  npm run dev-server
```
then continue with the normal test flow.

If the browser sign-in window does not appear and sideloading times out, the documented recovery step is to run atk auth login m365 and then retry sideloading.

References:

Answer 2

Hin Vo 445 Independent Advisor

Hi @Ronald Taff

Based on your description, the issue appears to be related to Microsoft 365 authentication during the Excel Add-in sideloading process. As far as I know, this type of issue is commonly associated with local authentication, Microsoft 365 tenant policies, or the Office Add-in development tooling rather than the add-in code itself.

To troubleshoot, you could try to follow these steps:

Sign out of all Microsoft 365 accounts in Office applications, then sign back in using the intended development account.

Verify that the account can successfully access Microsoft 365 services, such as: https://portal.office.com

Close all Office applications, reopen Excel, and attempt the sideloading process again.

If multiple Microsoft 365 accounts are signed in on the device, test with only the affected account signed in.

Ensure that your Office Add-in development tooling is updated to the latest version.

Please give the above steps a try and let me know the results.

Any update would be appreciated.

Ronald Taff 0 Reputation points

2026-08-09T23:25:11.2533333+00:00

Thanks for your response @Hin Vo I appreciate it. I tried those steps but no change.

This is my first time at creating a javascript add-in. I'm converting VBA and VSTO to JS/TS. I've been following the Microsoft tutorial on learning how to create a JS/TS add-in and up until now all good. I've pasted my screen print of what I'm seeing. This was ran using npm start. I've confirmed it's authenticating successfully with M365 but the following error(s) is what my results are. Please help if you can.

C:\Users\Admin\test\My Office Add-in>npm start

npm notice run office-addin-taskpane@0.0.1 start

npm notice run office-addin-debugging start manifest.json

Debugging is being started...

App type: desktop

Enabled debugging for add-in b733ef57-858c-4c60-8361-8a3f1274f48d.

Starting the dev server... (webpack serve --mode development)

The dev server is running on port 3000. Process id: 15972

Sideloading the Office Add-in...

Manifest package saved to C:\Users\Admin\AppData\Local\Temp\manifest.zip

running: npx @microsoft/teamsapp-cli install --file-path "C:\Users\Admin\AppData\Local\Temp\manifest.zip"

Log in to your Microsoft 365 account - opening default web browser at https://login.microsoftonline.com/common/oauth2/v2.0/authorize?client_id=7ea7c24c-b1f6-4a20-9d11-9ae12e9e7ac0&scope=https%3A%2F%2Ftitles.prod.mos.microsoft.com%2F.default%20openid%20profile%20offline_access&redirect_uri=http%3A%2F%2Flocalhost%3A53193&client-request-id=58609acf-6d27-4d22-950d-a5bfd4bb2077&response_mode=query&response_type=code&x-client-SKU=msal.js.node&x-client-VER=2.6.6&x-client-OS=win32&x-client-CPU=x64&client_info=1&code_challenge=TjUjcouBvVw55ex2hcfQKuFgt7eQ58FhPDFOYzrenyI&code_challenge_method=S256&prompt=select_account#

[Login] Failed to retrieve token silently. If you encounter this problem multiple times, you can delete C:\Users\Admin\.fx\account and try again. invalid_scope: 70011 - [2026-08-09 23:11:19Z]: AADSTS70011: The provided value for the input parameter 'scope' is not valid. The scope 'https://dev.teams.microsoft.com/AppDefinitions.ReadWrite openid profile offline_access' does not exist. Trace ID: [Moderator note: personal info removed] Correlation ID: [Moderator note: personal info removed] Timestamp: 2026-08-09 23:11:19Z - Correlation ID: [Moderator note: personal info removed] - Trace ID: [Moderator note: personal info removed]

--Error sideloading!--

Error: Error: Command failed: npx @microsoft/teamsapp-cli install --file-path "C:\Users\Admin\AppData\Local\Temp\manifest.zip"

npm warn install-scripts .npmrc allow-scripts setting is being ignored because --allow-scripts was passed on the command line

npm notice run office-addin-taskpane@0.0.1 npx

npm notice run teamsapp install --file-path C:\Users\Admin\AppData\Local\Temp\manifest.zip

(node:18392) [DEP0044] DeprecationWarning: The util.isArray API is deprecated. Please use Array.isArray() instead.

(Use node --trace-deprecation ... to show where the warning was created)

(×) Error: Get ServiceUrl failed. Request failed with status code 403

(×) Error: m365.InternalError: Request failed with status code 403 (tracingId: ) :

STDERR:

npm warn install-scripts .npmrc allow-scripts setting is being ignored because --allow-scripts was passed on the command line

npm notice run office-addin-taskpane@0.0.1 npx

npm notice run teamsapp install --file-path C:\Users\Admin\AppData\Local\Temp\manifest.zip

(node:18392) [DEP0044] DeprecationWarning: The util.isArray API is deprecated. Please use Array.isArray() instead.

(Use node --trace-deprecation ... to show where the warning was created)

(×) Error: Get ServiceUrl failed. Request failed with status code 403

(×) Error: m365.InternalError: Request failed with status code 403 (tracingId: ) :

Error: Unable to start debugging.

Error: Unable to sideload the Office Add-in.

Error: Command failed: npx @microsoft/teamsapp-cli install --file-path "C:\Users\Admin\AppData\Local\Temp\manifest.zip"

npm warn install-scripts .npmrc allow-scripts setting is being ignored because --allow-scripts was passed on the command line

npm notice run office-addin-taskpane@0.0.1 npx

npm notice run teamsapp install --file-path C:\Users\Admin\AppData\Local\Temp\manifest.zip

(node:18392) [DEP0044] DeprecationWarning: The util.isArray API is deprecated. Please use Array.isArray() instead.

(Use node --trace-deprecation ... to show where the warning was created)

(×) Error: Get ServiceUrl failed. Request failed with status code 403

(×) Error: m365.InternalError: Request failed with status code 403 (tracingId: ) :

C:\Users\Admin\test\My Office Add-in>
Ronald Taff 0 Reputation points

2026-08-09T23:27:44.2833333+00:00

I feel pretty sure the issue lies within my configurations or environment. I just can't find it.
Ronald Taff 0 Reputation points

2026-08-10T01:01:12.7466667+00:00

Found that I needed to have a M365 business account instead of a personal account. Thanks for the help!
Hin Vo 445 Reputation points Independent Advisor

2026-08-10T07:19:08.1866667+00:00

Hi @Ronald Taff
Thank you for the update.

I'm glad to hear that you were able to identify the root cause. Based on your findings, the issue was related to the use of a personal Microsoft account rather than a Microsoft 365 Business (work/school) account.

Thank you for sharing the resolution. If you encounter any additional issues with your Office Add-in development, please feel free to reach out anytime.

Warm thanks.