How can I reconnect my AMEX account to Quickbooks? It worked before, but now gives an OAuth error

I had my AMEX account linked to quickbooks (Amex EUR, Finland), but the authorization period run out. I tried several times to reconnect, but it did not work. Then, I found advice to delete the account and relink it as new. I managed the deletion just fine, but am still unable to reconnect the account. Does anyone have any advice? This significantly reduces the utility of Quickbooks for me.