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Exclaimer Outlook Add-in repeated sign-in prompt in Classic Outlook

  1. Exclaimer Knowledge Base
  2. Solutions
  3. Other Solutions
Payal Arya
  • Updated

Scenario

The Exclaimer Outlook Add-in repeatedly prompts users in Classic Outlook with the message:

Please open the Exclaimer app and sign in to continue using the add-in (Sign in | Dismiss)

When this occurs, the Exclaimer Add-in fails to automatically insert the user’s signature into the email body, disrupting normal email composition. Restarting Outlook may temporarily clear the prompt and restore signature insertion, but the issue can reoccur unpredictably, even after the user has successfully signed in.

Reason

When composing an email, Classic Outlook needs the Exclaimer Add-in to authenticate the user before it can insert a signature. The Add-in tries to sign in silently in the background, but if this fails, Outlook prompts the user to sign in again. This usually happens due to a corrupted or outdated local Web Add-in Framework (WEF) cache in Classic Outlook, and it typically does not affect New Outlook or Outlook on the web.

Resolution

Follow these steps to resolve the issue:

We recommend: First, try reauthorising the client-side Enterprise app by following this guide: Enable Signatures to be downloaded for Outlook. 
Restart Outlook afterwards. If the sign-in message still appears, then proceed with the steps listed below 1–5.
  1. Close Outlook completely. Make sure Outlook is fully closed (including from Task Manager if needed).
     
  2. Open File Explorer and navigate to: C:\Users\<username>\AppData\Local\Microsoft\Office\16.0\
     

  3. Locate the Wef folder. Rename or delete it.  

    Tip! You can also delete the folder using PowerShell. Run the following script:

    Remove-Item "$env:LOCALAPPDATA\Microsoft\Office\16.0\Wef" -Recurse -Force -ErrorAction SilentlyContinue    

    This clears the local add-in cache.

  4. Reopen Outlook.
     

  5. Compose a new email and confirm the signature is inserted automatically.

    If the sign-in prompt no longer appears, the issue is resolved.

Troubleshooting - if you need assistance

If the issue persists:

  1. Open Outlook.
     
  2. Navigate to the File menu, then select Help.
     
  3. Select Get Diagnostics.
     
  4. Select Accept. Logs are typically located in C:\Users\<username>\Downloads
     

  5. Open PowerShell and run the following command as an Administrator, and copy the output:

    Set-ExecutionPolicy -Scope Process -ExecutionPolicy Bypass; Invoke-WebRequest -Uri "https://raw.githubusercontent.com/exclaimerltd/Internal-Support-Scripts/master/AddInChecks.ps1" -OutFile "$env:TEMP\AddInChecks.ps1"; & "$env:TEMP\AddInChecks.ps1"
  6. Raise a support ticket and include the diagnostic logs from Steps 3 & 4 and the PowerShell script output from Step 5. 

    This information will help the Support Team investigate the authentication and Add-in initialization issues further.