401 Unauthorized
Situations in the vault where SharePoint, SPFx, Microsoft Graph or the Azure services around them answer with HTTP 401. Each one explains why it happens and how to fix it.
- A mail-permission probe that can't tell "no mailbox" from "no consent" lies to adminsgotchas / graph/me/messages 404 MailboxNotEnabled* on mailbox-less accounts ≠ missing consent; three verdicts, and never cache a negative probe result
- Power Automate admin flows API returns UserImpersonationScopeMissing from SPFx – even after you approve the scopegotchas / spfxSharePoint's token for Microsoft Flow Service carries only Microsoft's preauthorized scopes, so an approved User grant never reaches the token and the tenant-wide flows list stays 401
- Uploaded .html grows after you set column values — SharePoint injects mso document properties (and rewrites Office files on upload)gotchas / rest-apiSetting column values rewrites the file; hash read-back fails for markup, holds for PDF; Office packages change on upload itself…