Developer reply by Philippe V.
Rated 5 out of 5 stars
As others have posted this add on no longer works with outlook.com or office365. No matter how many times you click validate it will just hang and never complete. Was working in the past but no longer after I had to create a new address book entry on a new system.
Works with Google and Yahoo contacts with no issues.
EDIT: Tested with developers 85.8 fix from Gitlab and worked perfectly once again with outlook.com. Thanks.
thanks a lot, will be fixed in 85.8 ! (here : https://gitlab.com/CardBook/CardBook/-/issues/1493#note_1379364187)
To create your own collections, you must have a Mozilla Add-ons account.