ADSError 857212673: Can't read variable values through name (pyads)

I've been having a problem lately where I can't access the value of any variable through their name. It's not a connection problem since I can read the value from the read() function just fine. However whenever I use the read_by_name function there's always the same error pyads.pyads_ex.ADSError: ADSError: Unknown Error (857212673).

Because it's an unknown error I haven't been able to find documentation on it. I'm using a BC9120 as a PLC and TwinCat 2. Does anyone know what might be causing this?

Code:

if self.plc.is_open == False:
    self.plc.open()
print(self.plc.read(pyads.INDEXGROUP_MEMORYBIT, 0*8 + 0, pyads.PLCTYPE_BOOL))  
print(self.plc.read_by_name("Test.M0", pyads.PLCTYPE_BOOL))

Logs:

False
Traceback (most recent call last):
  File "c:\Users\MAP9AV\Documents\Banca\Modelo Preditivo\Thread_Sup.py", line 50, in run
    print(self.plc.read_by_name("Test.M0", pyads.PLCTYPE_BOOL))
  File "C:\Users\MAP9AV\AppData\Local\Programs\Python\Python39\lib\site-packages\pyads\connection.py", line 540, in read_by_name
    return adsSyncReadByNameEx(
  File "C:\Users\MAP9AV\AppData\Local\Programs\Python\Python39\lib\site-packages\pyads\pyads_ex.py", line 1154, in adsSyncReadByNameEx
    handle = adsGetHandle(port, address, data_name)
  File "C:\Users\MAP9AV\AppData\Local\Programs\Python\Python39\lib\site-packages\pyads\pyads_ex.py", line 890, in adsGetHandle
    handle = adsSyncReadWriteReqEx2(
  File "C:\Users\MAP9AV\AppData\Local\Programs\Python\Python39\lib\site-packages\pyads\pyads_ex.py", line 774, in adsSyncReadWriteReqEx2
    raise ADSError(err_code)
pyads.pyads_ex.ADSError: ADSError: Unknown Error (857212673).