' Technical issue' notification from eBay, does not always explain the problem, it may well be something different.
You are not by any chance based in the Channel Isles? With Simple Delivery that Private sellers have to use, if they have Evri selected they lump the Chan. Isles into Europe, yep, and this can stop peeps from those places bidding or buying.
Or, do you have any unpaid item strikes?
If you have returned to buying on eBay after a long break, then bidding may be restricted, as sudden buying activity could be a sign that the account has been hijacked. So, eBay stop bidding and only allowing buying Buy it Now items with an immediate payment, once eBay are happy the original owner has returned, bidding rights are given back. It's a good security measure for your account.
If none of the above applies contact Customer Services they have access to your account and can hopefully see where the issue lies.
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 recommend contacting CS first thing in the morning as there's more chance of Dublin answering.
@lyndnewto_6