KeyCDN is a content delivery network based in Switzerland. Websites use it to serve images, scripts, stylesheets and downloads from edge servers close to visitors, so pages load faster and the origin server carries less load. Customers manage everything through the KeyCDN dashboard, where each site is set up as a zone.
The live test at the top of the page calls keycdn.com from a third-party server and shows the reply, its speed and the certificate in use. That tells you whether KeyCDN’s own website is up. Your zones run on the edge network, so a separate test against your own files is the next step if assets are failing.
Is it the CDN, the origin or the cache
When files served through KeyCDN break, the cause falls into one of three places.
The origin. In a pull zone, KeyCDN asks your server for each file the first time and caches it. If your server is down, overloaded or blocks the CDN’s requests with a firewall rule, the edge has nothing to deliver. This is the most common cause of gateway errors.
The cache. A broken file that got cached keeps being served until it expires or is purged. Fixing the origin is not enough in that case; the cached copy has to go too.
The network. Edge locations, routing and DNS for the zone are KeyCDN’s responsibility. Problems here tend to hit one region at a time and appear on the status page.
Tracing a CDN error
- Request the file from the origin
Open the same path on your own server. If it fails, the CDN is not the problem.
- Request it through the zone URL
Compare the response with the origin. Different content means a stale or bad cached copy.
- Purge the affected URL
Use the purge option in the dashboard, then request the file again.
- Check your DNS
If you use a custom CDN hostname, its CNAME record must point at your zone. A typo or a removed record sends visitors nowhere.
- Look at the certificate
Custom hostnames need a valid certificate on the zone; an expired or missing one shows as a browser security error.
- Compare regions
Ask someone in another country to test, or use the status page to see if one location has an incident.
Errors you may see
| What you see | Likely cause | What to try |
|---|---|---|
| 502 or 504 on CDN files | Origin slow or refusing the CDN | Check origin load and firewall |
| Old file version keeps appearing | Cached copy not yet expired | Purge the URL or zone |
| Certificate warning on the CDN hostname | Missing or expired zone certificate | Renew or reissue it in the dashboard |
| Files fail in one region only | Edge location issue | Check the status page by location |
| Dashboard does not load | Website or account problem | Run the check above, try another browser |
Reading the result
A reachable result shows KeyCDN’s website and dashboard front end are answering. It does not prove every edge location is healthy, and it says nothing about your origin. A slow or unreachable result is worth confirming on the status page, because KeyCDN reports edge incidents there with the affected locations. When you open a ticket, include an example URL and the response headers, so support can see which edge served the request.
Response headers that show which edge answered
KeyCDN adds headers to responses from a zone that make troubleshooting much faster. X-Edge-Location names the point of presence that served the request: the first two letters are the country, the last two the city, so usse stands for Seattle. X-Cache shows whether the file came out of the edge cache. HIT means the edge already held it; MISS means the edge had to fetch it from your origin. KeyCDN’s CDN troubleshooting guide lists four more values, EXPIRED, REVALIDATED, UPDATING and STALE.
A file has to be requested at least twice through the same edge before a HIT can appear, so a MISS on the first test is expected and proves nothing. Running curl with the -I option against the zone URL prints these headers in a second. KeyCDN’s free web tools, including its performance test, request a URL from several locations at once and show the X-Edge-Location for each, which is the quickest way to spot one bad region.
When one location keeps returning a MISS or an error while others serve HITs, that edge cannot fetch from your origin, often because of a firewall rule or country blocking on the origin server. The overview of 5xx gateway errors explains the 502 and 504 responses that usually go with that case. Put the X-Edge-Location value next to the full URL in any support ticket.
Official KeyCDN help
- KeyCDN Statusstatus.keycdn.com
- KeyCDN Supportkeycdn.com/support
- KeyCDN on X@KeyCDN
Questions about KeyCDN
My site's images fail to load. Is KeyCDN down?
Possibly, but check your origin first. KeyCDN fetches files from your own server, and if that server is slow, misconfigured or blocks KeyCDN's requests, the CDN returns errors too. Request the same file directly from the origin. If that fails, fix the origin; if it works, look at the zone settings and the KeyCDN status page.
What is the difference between a pull zone and a push zone?
A pull zone fetches files from your origin server on demand and caches them. A push zone stores files that you upload to KeyCDN directly. Pull zones depend on your origin staying healthy; push zones depend only on KeyCDN's storage and edge servers.
Why does my site still show the old version of a file?
The edge servers keep a cached copy until it expires or you purge it. Purge the zone or the specific URL in the KeyCDN dashboard. For files that change often, add a version string to the file name or set a shorter cache time on the origin.
Why do some visitors see errors and others do not?
Visitors reach different edge locations depending on where they are. A problem at one location, or a cache that holds a bad response in one region, affects only part of your audience. The KeyCDN status page lists incidents by location.
Does a 502 or 504 from the zone mean KeyCDN failed?
Not necessarily. These gateway errors usually mean the edge server could not get a good answer from your origin in time. Look at the origin's load, firewall rules and response times. If the origin is healthy and the errors persist, contact KeyCDN support with an example URL and time.
Does the check on this page test my own zone?
No. It tests the KeyCDN website. To test your zone, request one of your files through the zone URL or your custom CDN hostname and compare it with the same file from the origin.