507 Insufficient Storage (RFC 4918, WebDAV) means the method could not be performed because the server is unable to store the representation needed to complete the request. The condition is considered temporary, for example until files are deleted or the quota is raised.
WebDAV and file-sync servers use it when a user's quota or the server's disk is full; RFC 4331 defines the quota-not-exceeded precondition for this case. Some other APIs use 507 for storage or capacity problems too.
Example response
HTTP
HTTP/1.1 507 Insufficient Storage
Date: Fri, 06 Nov 2026 10:15:32 GMT
Content-Type: application/xml; charset=utf-8
Content-Length: 100
<?xml version="1.0" encoding="utf-8"?>
<d:error xmlns:d="DAV:">
<d:quota-not-exceeded/>
</d:error>SEO and redirect checking
507 normally affects uploads, not page views, so it rarely matters for SEO. If a public page returns 507, the application most likely cannot write data it needs, such as sessions or cache files, because a disk or quota is full.
Common causes and use cases
- A user's storage quota on a WebDAV or file-sync service is used up.
- The server's disk is full.
- A temporary directory used for uploads or sessions has no free space left.