All Company Community: Posting Error

Because uploads still work in other communities, start with the All Company community's configuration and storage rather than assuming your browser or file is universally blocked. Test a small, harmless image and document there, and check whether another ordinary member experiences the same error. Also distinguish a plain-text post from one containing an attachment. Microsoft documents SharePoint as the usual storage backend for community files, so ask an administrator to identify this community's actual storage location and check its access permissions and availability. Where SharePoint storage applies, review relevant Conditional Access failures as well; do not weaken those policies just to test uploading. Record the UTC time, file type, browser and whether the same file succeeds elsewhere. If multiple members reproduce it, have the administrator check service health and escalate with those comparisons. Avoid repeatedly submitting the same post while the outcome is uncertain.