I had this same problem. This is how I fixed it.

Log out of all devices (don't worry, your things won't disappear as long as you don't uninstall it). Close Opera. Sign in https://sync.opera.com/web/ Click on "Redefine your data" (it won't erase your local settings) Change your password here https://auth.opera.com/account/edit-profile and log out. Open Opera at home Go to Settings and Login Click on "Choose what to sync" or something like that Choose whatever you want to sync, but don't encrypt your data for now. Login Opera at work.

If everything works fine, you may encrypt your data but you will have to login again.
This worked for me.