#guests 3 articles

• An unencoded # in a $filter value cuts the URL — SharePoint gets half a query and answers 400gotchas / rest-apiThe browser drops everything after # as a fragment, SharePoint gets an unterminated literal and answers 400; guest UPNs (#EXT#) always hit it; & cuts the expression and a raw + arrives as a space, so a valid literal…
• Guests cannot join a Teams shared channel — only people from another Microsoft 365 organisation cangotchas / permissionsShared channels admit external people only through B2B direct connect between two Entra tenants; a guest account cannot be added, so a partner without their own Microsoft 365 needs a different design
• The Microsoft Graph JS client sends $filter values unencoded — & splits the query, # cuts it offgotchas / graph.filter(), .query() and .api('…?…') pass the value into the URL as-is (SDK 3.0.2, also under SPFx MSGraphClientV3): # cuts the query, & splits it and .api() even moves $top into the filter; double apostrophes, then…