The thin clients stay at ‘contacting file server’ when connected to the new switch. With the old switch everything works. The new switches are Allied Telesis AT-8000S and AT-8000GS. The switches use the default VLAN and I created a trunk between 2 switches. The old switches are unmanaged D-Link switches. The thin clients have a static ip-address.
ftp server log thin client connected to new switch: