When using Lookback from home – either as the moderator or Participant – you may run into the error message "Failed to Fetch" while trying to connect. This error means that somewhere between you and Lookback there is something blocking your connection. In fact, some of these issues may even prevent you from logging in to Lookback altogether. Connectivity issues are often hard to pinpoint, because there are many parameters involved, and the block could exist on many different levels. In this article we will lay out a few things you can check, to try to pinpoint the problem.


Jump to:

  1. Troubleshooting firewall related issues

  2. Troubleshooting ad-blocker related issues


Troubleshooting Firewall Related Issues

  • Office VPN from home. If you're working from home but you're connecting via your office's VPN or using a VPN and seeing errors such as the one above you'll need to ask your network administrator to review our article on firewall troubleshooting for IT teams. If they are unavailable for some reason, we recommend disconnecting from the VPN during the session and while using Lookback until they have implemented the changes above as long as it does not violate any security policies.

  • Blocked at the ISP/router level. Most users connecting from their home internet will not run into firewall related issues, but if it happens, it's not unlikely your ISP (Internet Service Provider) has some sort of custom router or network configuration causing the issues. So, if you do encounter errors like "Failed to Fetch" we recommend you talk to whoever at your home manages the router to see if anything is being blocked. Alternatively, even if your router is not explicitly blocking traffic, it's possible you may need to explicitly allow traffic to and from Lookback's servers. You may also need to talk to your ISP to make sure that certain types of connections or connections to/from specific regions are not being blocked.

While we can't help with specific router configurations due to the wide variety of models and configurations, we can provide you with some details regarding how our systems try to establish a connection.

  • Configure your firewall – which ports? Our live streaming clients (for both IPv4 and IPv6) attempt to connect to our servers via a number of ports, as well as both UDP and TCP.

    When configuring your firewall the most performant ports to allow are 19305 - 19309 via UDP. We suggest opening ports in the following order of preference: 

  • UDP ports 19305 - 19309

  • TCP port 19305

  • TCP port 22466

  • TCP port 443

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Troubleshooting Ad-Blocker Related Issues

  • Ad-blockers are great when they block annoying ads, but they are for from a perfect solution. It's not uncommon they also incorrectly and unintentionally block other data/code, which can sometimes cause problems when trying to connect with normally functioning websites like Lookback.

  • If you're having trouble connecting to Lookback and you do have ad-blocking software activated, or an ad-blocking extension in your browser, try to disable it or – in case you can't disable it for security reasons or something similar – at least add an exception to that ad-blocking softward, so it does not try to block ads on any pages ending with lookback.io.

  • Additionally, some home routers offer ad-blocking features as an extra service, associated with the router. As an example, Amazon's Eero router series offer an ad-blocking feature with their Eero+ service. So, if you've tried addressing some of the things mentioned above, but you're still experiencing problems, you may need to add lookback.io to a list of exceptions here as well.

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