import json
from jsonschema import validate, ValidationError

schema = {
    "properties": {
        "Enabled": {
            "type": "string",
            "description": "Enable or disable Access.",
            "pattern": "^(?i)(on|off)$"
        }
    },
    "required": ["Enabled"],
    "additionalProperties": False,
    "type": ["object"]
}

data = '{"Enabled": "On"}'
data_dict = json.loads(data)

try:
    validate(instance=data_dict, schema=schema)
    print("Validation successful!")
except ValidationError as e:
    print(f"Validation error: {e.message}")

jsonschema.exceptions.SchemaError: '^(?i)(on|off)$' is not a 'regex'

Failed validating 'format' in metaschema['allOf'][1]['properties']['properties']['additionalProperties']['$dynamicRef']['allOf'][3]['properties']['pattern']:
    {'format': 'regex', 'type': 'string'}

On schema['properties']['Enabled']['pattern']:
    '^(?i)(on|off)$'