Time Machine support broken

Hi,

I have a file server in our network to which a few computers also write their Time Machine backups. Since yesterday morning, one Mac can no longer write a backup. The following error is displayed:

The selected backup volume on the network does not support the necessary functions.

Make sure that Time Machine support is enabled for this volume on the server, or select another network backup volume.

(translated from German)

I have already updated OMV to the latest version 6, deactivated and reactivated Time Machine under SMB in the shares, with an interim restart. None of this has helped. But the whole thing happened overnight. A backup was made in the evening and this error message appeared in the morning.

Other computers are not affected.

Does anyone have any idea how I can get this working again?

Thanks in advance

There were no changings on Mac side or server side. All computer were booted between test changes. All Macs are on the same OS version.

The only thing I didn't try yet was a new smb share. I tried that now and it is the same result. I get the same error.

YEs, it's the same here. I just had a look at the logs and found this at the Daemon logs. Always at the time when I try to add a Time Machine volume to my Mac.

smbd[46733]: process_usershare_file: share name /cifs._smb._tcp.local./hanstm3 contains invalid characters (any of %<>*?|/\+=;:",)

But neither in the username, nor in the password is any special character.

The solution was quite easy. TimeMachine didn't like the first capital letter in the username anymore. I created a new user only with small letters and it worked again.