Restore on Windows Client not Working

Hello,
i have a Problem with the urbackup windows client.

Backing up and restoring over the webinterface works fine, but when i want to restore something on a client machine by selecting “access backup” from the right-click menu, it shows me an error “Error Connecting to the Server” (As shown in the Screenshots).

Starting a Restore from the Webinterface, or a Backup from the Client works fine, since the issue is reproducible on all 3 clients i suspect a setting on the serverside, but don’t know which.

How can i Debug this?

Unbenannt Unbenannt2

Urbackup Version: 4.10 on the Client, 4.11 on the Server
Client is a Windows 10 Pro, The Server is running in a Freebsd Jail.

What ports are explicitly open on the server and client?

Client requires:

Port Usage Protocol
35621 Sending files during file backups (file server) TCP
35622 UDP broadcasts for discovery UDP
35623 Commands and image backups TCP

There is no firewall on the server and the client has the ports opened.

➜  ~ nmap -p 55413,55414,55415 192.168.100.3      
Starting Nmap 7.80 ( https://nmap.org ) at 2020-02-27 09:39 CET
Nmap scan report for 192.168.100.3
Host is up (0.0014s latency).

PORT      STATE SERVICE
55413/tcp open  unknown
55414/tcp open  unknown
55415/tcp open  unknown

Nmap done: 1 IP address (1 host up) scanned in 0.04 seconds
➜  ~ nmap -p 35621,35623 192.168.100.50 
Starting Nmap 7.80 ( https://nmap.org ) at 2020-02-27 09:39 CET
Nmap scan report for DESKTOP-18G1LST.sphairon.box (192.168.100.50)
Host is up (0.060s latency).

PORT      STATE SERVICE
35621/tcp open  unknown
35623/tcp open  unknown

Nmap done: 1 IP address (1 host up) scanned in 0.12 seconds

Also, when i start the server in Debug mode, i don’t see anything regarding this access in the log (i see the backups etc, but not a request regarding the “access backups”, so a network problem still seems plausible)