Sounds like a temporary site glitch. Worth waiting a little while, then trying again.
Try also switching devices and browser especially if using the app or mobile browser, switch if you can to a laptop / PC with Chrome see if that helps.
If this still fails contact eBay Customer Services see if they have a workaround or know how long it's going to take for a fix.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open 8 a.m. - 10 p.m. on weekdays
9 a.m. - 6 p.m. on weekends.
Automated agents will be available on chat outside of the above hours.
I do recommend contacting CS very first thing in the morning, when the lines first open, as there's more chance of Dublin answering.
@140489d0g