Why do I see the message "This replay cannot be played" in Session Replay player?

What are Unplayable replays? 

Unplayable replays are shown in the Player but display only a grey block in the UI. While Contentsquare has the page metadata (such as the pageview URL) we don't necessarily have the replay data for a particular page, making the replay unwatchable. 0-second or "unplayable replays" are expected behavior resulting from the intention of not collecting or known limitations. This occurs for a URL of a session, not whole sessions.

Here are a few things that can cause the issue:

• Slow connection. There might have been an issue with the user connection, and the pageview was not sent to our servers properly.
• Site users navigated too quickly. Before our Tag script could fully load, users engaged with your site, but our tag did not have enough time to collect and send the replay.

• Too many network requests. If too many requests are sent simultaneously, it can cause our Tag requests to be queued and delayed.

• User-device is disconnected from the network. If a device suddenly is disconnected from the network, shuts down, or the browser closes. 
• Intentional not-collecting. With URL sampling we collect only some URLs of a whole session, others are not collected and therefore not displayed. Sometimes replay quotas have been exceeded on your project or Personal Data blocking applied on the whole page prevents collecting. If an IP is blocked it will also not be tracked.
• Tag limitations. Collecting can be limited by heavy pages that are > 8 MB, complex shadow DOM, iFrames*, and artificial pageviews.

• Setting issues. If CS domains have not been adequately whitelisted or Webworkers have been disabled, or an override of XHR API causes upload requests to fail our Tag will not function optimally.  

If you are experiencing unexpected unplayable replay submit a support ticket to launch an investigation.