請求書のダウンロードができなくなった

I understand you're having trouble downloading your invoice PDF. You mentioned that after entering your MFA code, you're getting a "Bad Request" error and can't download the invoice.

Based on the information available, this appears to be an MFA authentication issue. When entering MFA codes, it's important to ensure you're using the correct, current code from your authenticator app. MFA codes refresh regularly (typically every 30 seconds), so make sure you're using the most current code displayed.

If you're consistently getting a "Bad Request" error after entering what you believe is the correct MFA code, you might want to:

1. Check that your authenticator app (like Google Authenticator, Authy, or Microsoft Authenticator) is properly synchronized with the correct time
2. Ensure you're entering the complete MFA code correctly
3. Try again with a fresh code when the authenticator generates a new one

If the problem persists, you may need to contact AWS Support directly for assistance with your specific invoice download issue. There's a dedicated contact form for MFA-related issues that can help resolve your access problems.
Sources
Invalid MFA Code | AWS re:Post
Unable to Access Account Due to MFA Issue – Request for Help | AWS re:Post