What it means
The server cannot produce a response matching the Accept headers. Client errors mean the request cannot be fulfilled as sent. The server is working, but the address, permission or request rate is the problem.
Common causes
Strict content negotiation or security modules rejecting a client.
How to fix it
Relax the Accept header, or review mod_security style rules.
If you are a visitor
Check the address for typos, sign in if the page needs it, and try again. If you believe the page should exist, tell the site owner.
If you own the site
Retrying the same request will not help until you change something (URL, credentials or timing). URLs that keep returning 404 or 410 are dropped from search results over time. 429 and 403 can block crawlers if they are too aggressive or blocked by a firewall. Run the HTTP status checker to see exactly what your URL returns, and use uptime monitoring to be told when it changes.
Frequently asked questions
What does HTTP 406 mean?
Not Acceptable: The server cannot produce a response matching the Accept headers.
Is HTTP 406 an error?
Yes. Client errors mean the request cannot be fulfilled as sent. The server is working, but the address, permission or request rate is the problem.
Does HTTP 406 affect SEO?
URLs that keep returning 404 or 410 are dropped from search results over time. 429 and 403 can block crawlers if they are too aggressive or blocked by a firewall.
Should I retry after HTTP 406?
Retrying the same request will not help until you change something (URL, credentials or timing).