@jdb Thanks for reaching out and sorry for the trouble, we need more details to understand what is happening and be able to fix it.
Please submit a bug report with the following info:
username of the account you tried to sync,
error message shown (if any),
a screenshot of vivaldi://sync-internals and the Sync settings page on vivaldi://settings/sync/ can help or
click on Dump Status on vivaldi://sync-internals and send us the content that appears in a small box below the button,
time when it happened,
detailed steps to reproduce the issue.
Please share the VB number you receive via email here so we can quickly follow it up internally.
Thanks in advance for your help 🙏