Can't access Jtag error

I am using a MAX 10 device: 10M04SCU169C8G

I used Quartus 17.0 to synthesize and build the FPGA

I have tried using the stand alone programmer versions 17 and 18.

I have tried two different byte blasters.

I have tried on three different computers, all of which have successfully configured Intel/Altera FPGAs in the recent past using the Byte Blaster

When I connect the Byte Blaster and do an "Auto Detect" it properly identifies the part. I have examined the JTAG signals with a scope and everything looks good.

When I try to do any programming operation, including "Blank-Check", I get :

Error (209040): Can't access JTAG chain

A little more background: I work for a company that does contract work. Normally I would be the engineer who did the initial board bring up. For this client, however, they wanted to do the initial bring up and came back to us only when there were issues they couldn't deal with.

The client obviously was able to program the FPGA as it has at least some functionality. There is a 'heartbeat' LED that is blinking in the expected pattern. The FPGA controls other power supplies which have properly sequenced up. So the MAX 10 obviously programmed properly at least once.

In searching this problem I spotted forum messages regarding the use of JTAG pins as general I/O. I actually didn't know I could do that! I am certainly not using any of the JTAG pins as I/O and they do not have any assignments in the .qsf file. The JTAGEN pin is pulled high.

I have tried programming with both the .sof and .pof files, same result.

When I attempt to program or blank check the programmer starts with:

Info (209060): Started Programmer operation at Fri Jul 10 16:19:28 2020
Info (209017): Device 1 contains JTAG ID code 0x0318A0DD

It obviously can communicate with the MAX 10 device as it is able to auto detect it and it can read the JTAG ID code.

Why can't it program/configure the part?

There is one possibility that I have been trying to research but I haven't figured out just yet, and that is the Security Bit. I have never used this option. As I don't know for sure what the client did when they initially loaded the .pof file it is possible that they set this bit.

If the security bit had been set, would it explain this behavior?
If so, how would I unset the bit?

Any other explanations?

Thank you

Rod