I am trying to pay one invoices and a donation on just giving, just keeps going round and round. Done a restart

Any antivirus/security software you can try turning off, or their "secure browsing" or "HTTPS scanning" features? Anything that could impact the connection, like a VPN, Norton, Malwarebytes and similar?

(If you have any privacy addons, try turning these off as well.)

You may like to check your cookie settings. Some settings stop third party cookies and if you pay on line, sometimes it will use a third party to take payment.