[Yandex Cloud documentation](../index.md) > [Yandex Cloud CDN](index.md) > Troubleshooting # Troubleshooting in Cloud CDN Below is the list of common issues with Cloud CDN and ways to fix them. * [CDN responds to file requests with 3xx codes (redirect)](#responses-3xx) * [CDN responds to file requests with 4xx codes (client error)](#responses-4xx) * [CDN responds to file requests with 5xx codes (server error)](#responses-5xx) * [Requests with the POST, PUT, PATCH, and DELETE methods are not available to users](#post-responses) * [Updated settings failed to apply to the resource](#changes-not-applied) * [CDN resource has the `Not active` status, preventing content delivery to users](#resource-not-active) * [What happens to a CDN resource when the billing account is suspended due to non-payment](#billing-account-blocked) * [Unable to configure the TLS certificate](#tls-certificate) * [CDN sends compressed files to users who do not request compressed content](#compressed-files) * [How to enable WebSocket support](#websocket-support) ## The CDN responds to file requests with 3xx codes (redirect) {#responses-3xx} Make sure to specify the following [resource](concepts/resource.md) settings: * Protocol used by the origins as the primary one (HTTP or HTTPS). If origins redirect requests from `http` URIs to `https` URIs, select HTTPS for the resource, and vice versa. * `Host` HTTP header value to which origins respond without redirects. > For example, if the header value is set to `www.example.com`, and origins redirect requests with this value to `example.com`, change the value in the settings to `example.com`. ## The CDN responds to file requests with 4xx codes (client error) {#responses-4xx} Make sure that: * The resource settings allow end clients to access content. * Origins return files in response to direct requests, bypassing the CDN. * Origins allow and correctly process requests that match the resource settings: * Over the specified protocol: HTTP or HTTPS. * With the specified value of the `Host` HTTP header and other headers. ## The CDN responds to file requests with 5xx codes (server error) {#responses-5xx} {% note info %} CDN servers do not support IPv6 and can only access sources at IPv4 addresses. {% endnote %} Make sure that: * Origins respond to CDN server requests within 5 seconds. * Origins allow and correctly process requests that match the resource settings: * Over the specified protocol: HTTP or HTTPS. * With the specified value of the `Host` HTTP header and other headers. Also, check the Cloud CDN status [here](https://status.yandex.cloud/en/dashboard?service=cloud%20cdn). ## Requests with the POST, PUT, PATCH, and DELETE methods are not available to users {#post-responses} By default, the `POST`, `PUT`, `PATCH`, and `DELETE` methods are not available in client requests. To find out whether you can use these methods, contact [support](https://center.yandex.cloud/support). When contacting, describe your use case. ## Updated settings failed to apply to the resource {#changes-not-applied} It may take up to 15 minutes for the new settings of the existing resource to apply to the CDN servers. After that, we recommend [purging the resource cache](operations/resources/purge-cache.md). ## The CDN resource has the `Not active` status, preventing content delivery to users {#resource-not-active} Resources can show as `Not active` due to receiving no user requests for 90 days or being deactivated manually. To make them active again, [enable](operations/resources/configure-basics.md) **End-user access to content** in the basic resource settings. To enable or disable resources, you need the `cdn.editor` role or higher. ## What happens to a CDN resource when the billing account is suspended due to non-payment {#billing-account-blocked} If your [billing account](../billing/concepts/billing-account.md) is suspended due to non-payment, access to content via the CDN resource gets [disabled](operations/resources/disable-resource.md#disable-resource). {% note warning "**Important note**" %} Lifting the suspension of a billing account does not restore access to content. [Enable](operations/resources/disable-resource.md#enable-resource) it on your own. {% endnote %} ## Unable to configure the TLS certificate {#tls-certificate} {% note info %} We no longer support the _automatic_ issue of Let's Encrypt® certificates for CDN resources. {% endnote %} Certificates from [Yandex Certificate Manager](../certificate-manager/index.md) are supported. You can [issue a new Let's Encrypt® certificate](../certificate-manager/operations/managed/cert-create.md) or [upload one of your own](../certificate-manager/operations/import/cert-create.md). The certificate must be located in the same [folder](../resource-manager/concepts/resources-hierarchy.md#folder) as your CDN resource. Below is an example of a CLI error you receive when the certificate and the CDN resource reside in different folders: ```bash ERROR: operation (id=bcdb6qaiw8mb********) failed: rpc error: code = InvalidArgument desc = folder ids of user and certificate don't match; operation-id: bcdb6qaiw8mb******** ``` ## The CDN sends compressed files to users who do not request compressed content {#compressed-files} Cloud CDN may send compressed files even if a user does not request compressed content. This may happen in the following cases: 1. First request from the client for the file not yet in the CDN cache had the `Accept-Encoding: gzip` header. The same header is provided to the [origin](concepts/origins.md). 1. The origin transfers the compressed file to the CDN cache but does not add the `Vary: Accept-Encoding` header. For example, this happens if you set an [Object Storage bucket](../storage/concepts/bucket.md) as the origin. In this case, the CDN cache saves the compressed file, which all clients will receive. Also, it is irrelevant whether their devices support compression or whether they add the `Accept-Encoding: gzip` header to their requests. To avoid this, [enable file compression](operations/resources/enable-compression.md). This way, Cloud CDN will always request non-compressed content from the origin, and if the client request has the `Accept-Encoding: gzip` header, it will compress files on its own without sending the header to the origin. ## How to enable WebSocket protocol support {#websocket-support} To enable the [WebSocket](https://en.wikipedia.org/wiki/WebSocket) protocol, contact [support](https://center.yandex.cloud/support). Specify the following: * Your use case for WebSocket. * Tasks you plan to address. * Approximate traffic size.