There are still some issues related to eBay integration authorization tokens expiring frequently. Our developers have made some improvements however they are still working on addressing the cause.
To re-enable an integration, please hit the Test button in integration config and if the test is successful, re-enable the channel.
If an error is returned, you would need to create a new token as described here - https://help.linnworks.com/support/solutions/articles/7000024275-ebay-token-expiry-generation
Please note that all order despatch notifications that might have failed as a result of this issue will be re-submitted automatically.