Disk Shows Removed - All Other Empty Drives "Error" With New Disk

We have a AX4-5i, with a DAE attached. It ran for some time without issue until about a month ago when a single drive reported failed. We ordered a new drive and replaced the failed drive, but this one also shows failed. We replaced the replacement with a KNOWN GOOD drive, and that STILL errors out, showing the drive is failed.

In the components monitor of Navisphere the drive in question shows "removed".  In addition, an attempt to add other known good drives to the DAE results in an orange light and the Navisphere reporting the drive as fauled. The three other drives in the DAE are currently active and functioning without issue.

We've tried absolutely everything we can think of here. Does anyone have any suggestions as to how to continue to troubleshoot and hopefully resolve this problem?