FTP Server stopped working

I am currently facing an issue where I can't use the FTP Server for a specific robot.
Usually I am able to do something similar to the below commands to read or write to a file:

ftp 192.168.1.1
bin
get example.ls

This usually results in '200 Port Successful', '150 Binary Data connection', and '226 Binary Transfer complete' messages, along with the actual file we wanted to receive. Currently, we only receive the '200 Port successful' message, but no file is received.

Furthermore, the Fanuc Web Server is not able to use the 'Error Listing' (http://192.168.1.1/MD/ERRALL.LS) and 'Current IO Values' (http://192.168.1.1/MD/IOSTATE.DG) links.

It seems that anything related to accessing or writing to the MD drive. We can resolve the issue temporarily (for 3 days or so) by restarting the robot to a Controlled Start, and then rebooting again via Cold Start.

Has anyone else seem anything similar to this issue before?

It turns out we had a defective FROM/DRAM module that eventually stopped working altogether.

We resolved the issue by doing the following by replacing the defective FROM/DRAM module on the motherboard and restoring a recent image backup.