@geigs
Make sure your operating system is new enough to support the eBay app. Try uninstalling the eBay app, restarting your device, then reinstalling the eBay app once more.
If that does not help, try using a browser to reach ebay.com. You may have to disable the feature that opens eBay browser links in the app by tapping and holding such a link and choosing "don't open in the app".
