Siemens S7-1200 Error reading S7ReadResponse. Error code = 8104

New to Siemens, using TIA Portal v18 with S7-1200.
Device connection in Ignition configuration shows Connected.
Ignition logs show "Error reading S7ReadResponse. Error code = 8104".
I have been testing two tags which I can find in PLC tags / Default tag table:
"ns=1;s=[PLC1]IW116" which is an analog input and shows in Ignition as "Bad"
"ns=1;s=[PLC1]M1.5" which is Clock_1Hz and shows in Ignition as "Error_Configuration"

I found mention to permit PUT/GET so I set this offline and did a compile / software (rebuild all) and download to device / software (all) or do I also need a hardware compile?
Protection / Access level was already Full access.
There was also a mention of turning off optimized access but I am not sure where this is.
I also tried restarting the Ignition gateway service.

Have you done this?,partner%E2%80%9D%20needs%20to%20be%20enabled.
The syntax for getting bits is X as: MX1.5
The optimized access is for Data blocks (DB's). Right-click the data block and set it OFF

EDIT 1: And YES, after changing anything in Hardware Configuration, you need to recompile and download HW config again...



Yes, the hardware compile worked for the analog and adding the X worked for the MX1.5.
Couldn't see data changing (poll rate 1s) so I changed to MX1.7 (0.5Hz).