What version number of the app are you using?
Make sure you have the latest version of the eBay app for your operating system. Older versions can be erratic.
If you have not already done so, try uninstalling the eBay app, then restart your phone, and try installing the latest version from the app store. The restart in between should ensure a clean install which may help if the problem was with a previous installation that did not finish cleanly.
If you cannot get the latest version of the app to work or your operating system does not support the latest version of the eBay app, try using a browser to reach ebay.co.uk instead.
