Modbus RTU - Write an ASCII text with function code 16 into HMI

Hi, I'm trying to write a text to be displayed in a ASCII box in HMI Modbus RTU device with Node-Red Modbus Write and Modbus Flex Write.
With Modbus Write node I tried to write registers individually with FC3 (register by register) but only the first character is displayed in the text box of the HMI. If I use FC16 to write the full text, I get the error: "Modbus exception 3". The same error is received if I use Modbus Flex Write with this code:

msg.payload = { value:[65,66,67,68,69,70,71,72,73,74], 
'fc': 16, 
'unitid': 1, 
'address': 90, 
'quantity': 10 } 
return msg

I manage to write and read different registers from HMI, but I'm missing something regarding ASCII text box.

Any help is greatly appreciated