“I have a Microsoft 365 Personal subscription. Outlook for Mac prompts me to sign in to OneNote when using ‘Send to OneNote’, and the sign‑in fails with a 500 Internal Server Error. This happens immediately after authentication.”

Hi, KLS

Sorry for this frustration. Here are some suggestions you can try:

First, fully quit Outlook and OneNote, then restore Office’s keychain permissions instead of deleting old entries, lock the login keychain in Keychain Access, reopen an Office app, allow access, sign in again, then test Send to OneNote. It is recommended because Office for Mac can fail sign-in if it cannot properly reuse keychain permissions.

If that still fails, open Send to OneNote and press Control + Shift + L to open the debug panel, then copy the Session ID/logs and send them through Help > Contact Support or feedback. That is Microsoft’s troubleshooting path for this add-in.

As a practical workaround, it is also suggested that you use Outlook on the web, preferably in Safari if available, or forward the message to ******@onenote.com until the Mac app path is fixed. That route has been recommended repeatedly when the desktop integration is the part that breaks.

Thank you for your patience in reading, I hope this information has been helpful to you. 

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Tried all these there is no Office15 in key chain, in print there is no option to send to one note , all responses tried none worked