I am not able to sign in - bad request

Question

When I try to setup business account with Microsoft 365 for my e-shop domain - just for 3 users, it just goes to error when I fill in the name, role and address of the company an I am not able to get through.

What can I do?? Error is on the picture.

Moved from Microsoft 365 and Office | Other

Answer 1

Hello @Jan Lan,

Thanks for posting your question in the Microsoft Q&A forum.

Based on the screenshot, the “BadRequest” error appears while completing the Microsoft 365 Business Basic trial signup, specifically when submitting the company details. This usually means the request sent from the browser during the tenant creation process could not be processed correctly.

This can happen due to browser session conflicts, cached data, or sometimes a temporary issue during tenant provisioning.

You can try the following steps:

1. Try again using an InPrivate / Incognito window

• Open a new InPrivate / Incognito browser window
• Go back to the Microsoft 365 signup page
• Start the setup process again

This avoids cached session data that may interrupt the request.

2. Clear browser cache and cookies If you are using a desktop browser:

• Clear cache and cookies
• Close the browser completely
• Reopen it and try again

3. Try another browser or device. For example:

• If you used Chrome, try Microsoft Edge or Firefox
• You can also test from another device to rule out local browser issues

4. Disable VPN or network filtering If you are using a VPN or strict network firewall, try temporarily disabling it and attempt the setup again.

Microsoft also has guidance explaining that sign-in or request errors such as Error 400 / Bad Request can occur when the request cannot be processed correctly due to browser, device, or network conditions. You can review the troubleshooting suggestions here: Error 400 when signing in - Microsoft Support

If the issue still occurs after trying the steps above, it would be helpful if you could confirm:

• Which browser you are using
• Whether the issue happens in an InPrivate/Incognito window
• Whether you tried another device or network

This information will help narrow down the possible cause.

Answer 2

and I tried different web browsers or the anonymous window...