Thanks for a quick response!
Maybe a firewall problem?
I have now explicitly punched another hole for incoming connections on the specified port, no difference.
The router is letting the port through correctly afaics.
Also, calendar sync works!
Do you use HTTP/2?
Sorry, what is that?
Are there entries in the Web server (error) log?
Good point.
/var/log/nginx/access.log after a single failed contacts sync:
IP.IP.IP.IP - username [27/Apr/2019:10:48:44 +0300] "PROPFIND /dav.php/addressbooks/username/unique-id-1/ HTTP/1.1" 207 1645 "-" "DAVx5/2.4.0.1-ose (2019/04/05; dav4jvm; okhttp/3.12.1) Android/9"
IP.IP.IP.IP - username [27/Apr/2019:10:48:44 +0300] "PROPFIND /dav.php/calendars/username/unique-id-2/ HTTP/1.1" 207 1480 "-" "DAVx5/2.4.0.1-ose (2019/04/05; dav4jvm; okhttp/3.12.1) Android/9"
IP.IP.IP.IP - username [27/Apr/2019:10:48:44 +0300] "REPORT /dav.php/addressbooks/username/unique-id-1/ HTTP/1.1" 207 16071 "-" "DAVx5/2.4.0.1-ose (2019/04/05; dav4jvm; okhttp/3.12.1) Android/9"
IP.IP.IP.IP - username [27/Apr/2019:10:48:45 +0300] "REPORT /dav.php/calendars/username/unique-id-2/ HTTP/1.1" 207 12869 "-" "DAVx5/2.4.0.1-ose (2019/04/05; dav4jvm; okhttp/3.12.1) Android/9"
/var/log/nginx/error.log after a single failed contacts sync:
2019/04/27 10:48:44 [crit] 31778#31778: *3998 open() "/var/lib/nginx/fastcgi/4/02/0000000024" failed (13: Permission denied) while reading upstream, client: IP.IP.IP.IP, server: , request: "REPORT /dav.php/addressbooks/username/unique-id-1/ HTTP/1.1", upstream: "fastcgi://unix:/var/run/php/php7.0-fpm.sock:", host: "site.tld:port"
I see “permission denied”, but frankly I don’t understand where it comes from. Permission on the phone or on the server?
I do run a firewall on my phone - NetGuard. Needless to say, DAVx5 is allowed to access the internet.
I made another test with the firewall disabled completely, and the error message is the same on both server and phone.
Again: Calendar sync works both ways!