Thank you for your very quick response and clarifications offered.
Perhaps you can offer some advice on how to break the login cycle, which after entering my password takes me to a Vivaldi Logo page.
Clicking on the Vivaldi Logo takes me to another general page with various choices, including Webmail, which invites me to download Vivaldi, and Mail, which takes me back to a Login page.
I just go round and round in circles, occasionally finding random pages like 2-factor authentication. It is taking me as long as 10 minutes to eventually find my Inbox or often give up for an hour or two.
There is something amiss somewhere, but the only response from Vivaldi Support informed that they could not reproduce the issue.
Initially, I had been using Windows 10 Pro on a Gigabyte A320 pc with Ryzen 3 processor.
Today, I am using Windows 10 [Home] on an Acer AX3300 with AMD Athlon II processor.
(A Windows Update has totally crashed my newer pc (Ryzen 3), hopefully temporarily.