Fix Send & Print or license problems caused by old firewall rules after an update
Signs of the problem
- Send & Print stops working after an update
- Your license isn't recognized even though your subscription is active
- Other online features stop responding
Why it happens
Each time Lychee Slicer updates, Windows can register the new version as a separate program and create a new firewall rule for it. Over time, old rules with different settings pile up, and the one that applies may block Lychee Slicer's connection. This can happen silently, especially if you're on a different type of network than usual (home vs public) the first time you open the new version.
How to fix it
- Close Lychee Slicer completely.
- Open Windows Defender Firewall → Advanced settings.
- In Inbound Rules, find every entry named Lychee and delete it. Do the same in Outbound Rules.
- Open Lychee Slicer again. Windows asks whether to allow it through the firewall.
- Allow access on both private and public networks.
Test by slicing a simple file and using Send & Print.
Still not working?
Make sure you're on the latest version (see Install, Update or Roll Back Lychee Slicer), then contact us through the contact form with your Lychee Slicer version and a screenshot of the error.