Image backup Fail / component list loading

Hello

i have different clients running on m server, with 1 i have a problem

The Image backup tabs missing in the client (in the settings on the server all options are the same a a working client)

When i like to open the Windows components list on the client
the only thing i see is “Loading…”

when i try to start a image backup from the serverside , it takes an half hour and then i get :
Info
26-09-17 15:16
Starting unscheduled full image backup of volume “G:”…
Info
26-09-17 15:16
Basing image backup on last incremental or full image backup
Waarschuwingen
26-09-17 15:16
Error retrieving last image backup. Doing full image backup instead.
Fouten
26-09-17 15:46
Client disconnected and image is not persistent (Timeout: true).
Info
26-09-17 15:46
Transferred 766 bytes - Average speed: 0 Bit/s
Info
26-09-17 15:46
Time taken for backing up client CLIENTNAME: 30m
Fouten
26-09-17 15:46
Backup failed

what goes wrong?
reinstalling the client doesnt fix the problem.