@jumpsq Thanks for your feedback and sorry for the trouble.
about the login on android, please file a bug report on vivaldi.com/bugreport so we get more details about your setup and understand what is going on.
it depends on the calendar client indeed. Which link have you used? If possible, try using https://calendar.vivaldi.net/calendars/ which is more generic.
tasks are currently not supported.
Thanks in advance for your help
Seems you're having some growing pains... I don't mind SMS verification but you have bigger problems. You still need to clean up the login, re-logging problems. I've re-logged 3 or 4 times to get to leave a message. Looking forward to using my new browser. I like it, lots! Fast, clean etc. Please allow extensions as my password manager needs a spot in your browser.