diff --git a/pymelsec/exceptions.py b/pymelsec/exceptions.py
index 591e238..3011e29 100644
--- a/pymelsec/exceptions.py
+++ b/pymelsec/exceptions.py
@@ -12,7 +12,10 @@ class MCError(Exception):
     """
 
     def __init__(self, errorcode):
-        self.errorcode =  f'0x{str(errorcode).rjust(4, "0").upper()}'
+        if isinstance(errorcode, str):
+            self.errorcode =  int(f'0x{errorcode.rjust(4, "0").upper()}', 16)
+        elif isinstance(errorcode, int):
+            self.errorcode = errorcode
 
 
     def __str__(self):
@@ -71,6 +74,7 @@ def __str__(self):
         elif self.errorcode == 0xC204:
             return (f'{self.errorcode}: The connected device is different from the one that requested for '
             'unlock processing of the remote password.')
+        return f'{self.errorcode}: Unknown error.'
 
 
 class DataTypeError(Exception):