Empty CardDAV address book in Thunderbird

[kdato]

Your environment

TbSync version: tried TbSync (2.16) + Provider for CalDAV & CardDAV (1.19) from Thunderbird add-ons; also tried the latest betas

Thunderbird version: 78.4.1 (64-bit), latest as of today; issue existed with previous versions

[x] Yes, I have installed the latest available beta version from https://tbsync.jobisoft.de and my issue is not yet fixed, I can still reproduce it.

Expected behavior

Display contacts from mailo.com in Thunderbird.

Actual behavior

Thunderbird’s “Address Book” shows the Mailo directory with the Provider for Cal DAV & Card DAV icon. However, no contacts are displayed, the directory is empty.

Steps to reproduce

TbSync and CalDAV & CardDAV installed fine. mailo.com’s sync URL:Port for Thunderbird is https://carddav.mailo.com/adbook/[email protected]/1:443

When configuring Provider for CalDAV & CardDAV, I choose manual config and enter URL:Port as shown (alongside my Mailo username and password).

Provider for CalDAV & CardDAV synced fine and I get a green tick mark. In Thunderbird’s “Address Book”, I right-click on mailo.com and choose "Default startup directory". I then restart Thunderbird. However, the “Address Book” directory is empty, Thunderbird does not display my Mailo contacts.

For cross-reference, I was able to see my contacts in previous versions of Thunderbird with SOGO connector, which means that Mailo's URL:Port works.

There is a debug.log in TbSync Account Manager -> Help, which I emailed as instructed.