If your eBay channel shows as disconnected in Sellbrite, it's usually caused by something that happened outside of Sellbrite. The most common causes are changing your eBay password or trying to renew your eBay token while logged into a different eBay seller account in your browser.
How to reconnect your eBay account
Log out of your eBay seller account in your browser.
Open an Incognito browser tab.
Navigate to Settings > Sales Channel Integrations.
Select Connect a New Channel.
Select Connect under eBay.
Follow the connection instructions.
Note: Do not delete your disconnected eBay channel before doing this. On the Connect a New Channel page, eBay will already show as connected. Select Connect anyway.
Once you finish the steps, Sellbrite redirects you back to your Sales Channel Integrations page, where you'll see your eBay channel reconnected.