Dear Lou
Thanks for reaching out! Welcome to Microsoft Q&A. I'm Haien from Microsoft Q&A.
Based on the problem description, "the sign in button on Copilot does not respond," this issue is often related to a conflict in the authentication process. The Windows Copilot app is a bit unique because its sign-in functionality is closely tied to your default browser, specifically Microsoft Edge, and your user account settings on Windows.
To help me provide the most accurate solution:
- could you please clarify if you are trying to sign in with a personal Microsoft account or a work/school account?
- You are using Copilot via app or browser?
Here are some effective ways to work on:
- Go to Settings > Accounts > Email & accounts and confirm your personal Microsoft account is listed. If Copilot is accessing the wrong account, try switching to your personal account in Settings > Accounts > Your info > Sign in with a Microsoft account instead.
- If you are using Copilot apps: Go to Settings > Apps > Installed apps > Find Microsoft Copilot in the list > Click the three dots (...) next to it > select Advanced options > First, try the Repair option. If that doesn't work, proceed with the Reset option.
- Open the Get Help app, search for "Copilot license troubleshooter" > follow the steps to check for firewall or network blockers.
For additional information, please visit these articles: I can't sign in to my Microsoft account - Microsoft Support and Copilot troubleshooters - Microsoft Support
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We appreciate your patience and look forward to resolving this quickly for you.
Warm regards