Clear your cookies – In Chrome go to three dots in the top right-hand side

> Settings > Privacy and Security > Clear browsing data >
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Change Time range to All Time, tick the Cookies and other site data tick box only and select Clear data.
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Allow third-party cookies -
In Privacy and Security > Third-party Cookies > select Allow third-party cookies.
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Run through step 1 & 2 process twice, this is to check the process has worked, close and re-open Chrome each time. If you can go through the process with only one Tab, we suggest open with www.bbc.co.uk (not eBay or optiseller.com) or similar website each time.