Try to ping from the DSS side:

Go to the Console then enter CTRL + ALT + T then Ping.

Also you can check the logs for the dmesg, test (look at the RX side of the Ethx to see any packet errors), critical and error logs to see if there are more errors that might help.

Logs can be found in the GUI from Status > hardware > logs - then click on the download button.

You can also try to change the MaxRecvDataSegmentLenght and
MaxXmitDataSegmentLenght to 65536 to see if that helps if there are not other reasons.