Rated 3 out of 5 stars

Cannot upload my addresbook, it says:

"21 gru 2021, 11:33:25
Thunderbird start 21 gru 2021, 11:32:29
Start upload (remote)
- My_addressbook. (lastMod=before appstart) ...Error 400"

Addressbooks synchronizer v4.2
Thunderbird v 91.4.1 (x32)

It's not a webserver issue - the download functionality works like it should.
Error 400 not shows up when trying upload directly from plugin settings, it says only:
"Start upload (remote)
- My_addressbook. (lastMod=before appstart) ...method not allowed (7)"

This review is for a previous version of the add-on (4.2). 

Error 400 is an error from your webserver. Please check the setting of host/path, user and password