A family of Microsoft products that enable users to capture, organize, and reuse notes electronically.
Hi chadposey,
We appreciate that you posted back and confirmed the information with us.
May I know if you have tried the suggestion I provided above? If not, you can go to click the Start menu > Type Credential Manager > Under Windows Credentials, clear off all credentials underneath of Generic Credentials and then restart your computer. Then you can sign in OneNote with the correct account to check if the same problem will occur.
At the same time, we have searched a lot according to the error message you provided, we have found a related article: HTTP Error 407 Proxy authentication required
Disclaimer: Microsoft provides no assurances and/or warranties, implied or otherwise, and is not responsible for the information you receive from the third-party linked sites or any support related to technology.
In the meantime, could you provide the information below to help us troubleshoot this issue?
- According to your description, it seems that you are using OneNote for Windows 10, if so, please go to OneNote for Windows 10 > Settings > About to provide the screenshot of OneNote version.
- Please also go to OneNote Online to check if you can access the notebooks, if so, you can Open in app to check if the same problem will occur.
Best Regards,
Sukie