I was trying to delete an entry in my online accounts (since I restored Ubuntu 18.04 files over 17.10), and it wasn’t getting deleted.
The solution is to edit the following file:
~/.config/goa-1.0/accounts.conf
Then simply remove the entry you wish to delete.
Open Online Accounts again, and it’s gone!
Enjoy!
Source:
https://bugs.launchpad.net/ubuntu/+source/gcr/+bug/1044549/comments/14